Pheochromocytoma and paraganglioma: an endocrine society clinical practice guideline

Management of Pheochromocytomas and Paragangliomas

Pheochromocytomas and paragangliomas are distinctive neuroendocrine tumors which frequently produce excess catecholamines with resultant cardiovascular morbidity. These tumors have a strong genetic component, with up to 40% linked to hereditary pathogenic variants; therefore, germline genetic testing is recommended for all patients. Surgical resection offers the only potential cure in the case of localized disease. Given the potential for catecholaminergic crises, appropriate perioperative management is crucial, and all patients should undergo alpha-adrenergic blockade before resection. Therapeutic options for metastatic disease are limited and include surgical debulking, radiopharmaceutical therapies, and conventional chemotherapy.

'Essential' arterial hypertension: time for a paradigm change

The exclusion of causes of hypertension is not systematically exploited in clinical practice. Therefore, essential hypertension is consistently presented as the most prevalent 'cause'. The paradox of a condition with unknown causes being described as a common cause of hypertension translates into a diagnosis of essential hypertension in most patients, which precludes the detection of a curable cause of hypertension. The aim of this review is to investigate how the notion of essential hypertension has developed and whether scientific evidence still support the notion of its high prevalence by examining the most recent studies. These studies provided solid scientific evidence that, when systematically sought for, secondary hypertension is quite common and that secondary hypertension is highly prevalent. The increased awareness should lead to a systematic search for, with the goal of curing or achieving a better control of high blood pressure, and ultimately improving patients' quality of life.

Evaluation of Adrenal Incidentaloma

Adrenal incidentalomas have increased due to advanced and more sensitive imaging modalities, their increased utilization, and the aging population. Most adrenal incidentalomas are nonfunctional and benign, but a subset of patients has functional and/or malignant tumors. The evaluation of patients with an adrenal incidentaloma involves addressing 2 clinical questions: (1) Is the tumor functional? (2) Is the tumor malignant? A careful history and physical examination focused on signs and symptoms of adrenal functional tumors, biochemical testing, and imaging features are the cornerstone in the evaluation of patients with an adrenal incidentaloma.

Preoperative prediction of metastatic pheochromocytoma and paraganglioma using clinical, genetic, and biochemical markers: A cohort study

BACKGROUND

The prevalence of metastatic pheochromocytoma and paraganglioma (PPGL) is approximately 15%-20%. Although there are indicators to assess metastatic risks, none of them predict metastasis reliably. Therefore, we aimed to develop and validate a scoring system using clinical, genetic, and biochemical risk factors to preoperatively predict the metastatic risk of PPGL.

METHODS

In the cross-sectional cohort (n = 180), clinical, genetic, and biochemical risk factors for metastasis were identified using multivariate logistic regression analysis, and a novel scoring system was developed. The scoring system was validated and compared with the age, size of tumor, extra-adrenal location, and secretory type (ASES) score in the longitudinal cohort (n = 114).

RESULTS

In the cross-sectional cohort, pseudohypoxia group-related gene variants (SDHB, SDHD, or VHL), methoxytyramine >0.16 nmol/L, and tumor size >6.0 cm were independently associated with metastasis after multivariate logistic regression. Using them, the gene variant, methoxytyramine, and size of tumor (GMS) score were developed. In the longitudinal cohort, Harrell's concordance index of the GMS score (0.873, 95% confidence interval [CI]: 0.738-0.941) was higher than that of the ASES score (0.713, 95% CI: 0.567-0.814, p = 0.007). In the longitudinal cohort, a GMS score ≥2 was significantly associated with a higher risk of metastasis (hazard ratio = 25.07, 95% CI: 5.65-111.20). A GMS score ≥2 (p < 0.001), but not ASES score ≥2 (p = 0.090), was associated with shorter progression-free survival.

CONCLUSION

The GMS scoring system, which integrates gene variant, methoxytyramine level, and tumor size, provides a valuable preoperative approach to assess metastatic risk in PPGL.

[Adrenal tumors: current standards in clinical management]

Adrenal tumors are among the most common tumors in humans. They are most frequently discovered incidentally during abdominal imaging for other reasons or due to clinical symptoms (e.g. Conn's or Cushing's syndrome, pheochromocytoma or androgen excess). Although over 80% of adrenal tumors are benign, in cases of hormone excess, they are associated with significantly increased morbidity. In highly malignant adrenocortical carcinoma (ACC), early diagnosis is of particular prognostic relevance. Therefore, this review presents the diagnostic procedure for what are referred to as adrenal incidentalomas and provide recommendations for the management of ACC and pheochromocytomas/paragangliomas (PPGL). In primary diagnosis, sufficient hormone diagnostics is required for all adrenal tumors, as this is the only way to identify all patients with relevant hormone excess. Imaging has increasingly improved in recent years and allows a reliable assessment of the tumor's malignancy in most cases. Imaging of first choice is unenhanced computed tomography (CT), while magnetic resonance imaging (MRI) and fluorodeoxyglucose-18 positron emission tomography (FDG-PET/CT) are reserved for special situations, as published evidence on these procedures is more limited. The treatment of ACC and PPGL is complex and is carried out on an interdisciplinary basis at specialized centers. In the case of localized disease, surgery is the only curative treatment option. There are now clear recommendations for individualized adjuvant therapy for ACC. In metastatic disease, mitotane with or without platinum-containing chemotherapy is the standard. Other lines of therapy should be discussed with a reference center. Over 35% of PPGL have a germline mutation; therefore, genetic testing should be offered. In metastatic PPGL, an individual decision is required between active surveillance, radionuclide therapy, sunitinib or chemotherapy.

Validation and Evaluation of 5 Scoring Systems for Predicting Metastatic Risk in Pheochromocytoma and Paraganglioma

Currently, 5 scoring systems have been proposed in the literature for predicting metastatic risk in pheochromocytoma and paraganglioma (PPGL): Pheochromocytoma of the Adrenal Gland Scaled Score (PASS), Grading System for Adrenal Pheochromocytoma and Paraganglioma (GAPP), Composite Pheochromocytoma/paraganglioma Prognostic Score (COPPS), Age, Size, Extra-adrenal location, Secretion type (ASES) score, and Size, Genetic, Age, and PASS (SGAP) model. To validate and evaluate these 5 scoring systems, we conducted a retrospective review of cases diagnosed as PPGL at the Department of Pathology, West China Hospital of Sichuan University, between January 2012 and December 2019. A total of 185 PPGL cases were included, comprising 35 cases with metastasis and 150 cases remained metastasis-free for over 8 years after surgery. The criteria of the 5 scoring systems were used for scoring and risk classification. The predictive performance of the 5 scoring systems was validated, compared, and evaluated using concordance index (C-index) and decision curve analysis (DCA). The C-indices for PASS, GAPP, and SGAP were 0.600, 0.547, and 0.547, respectively, indicating low discriminative ability. In contrast, COPPS and ASES had C-indices of 0.740 and 0.706, respectively, indicating better discriminative performance. DCA also showed that the predictive capability of COPPS was superior to that of ASES, with both outperformed PASS, while PASS had better predictive ability than GAPP and SGAP. Our analysis indicated that pathology-based scoring systems cannot accurately predict metastatic risk of PPGL. Establishing a precise prediction system requires integrating clinical, pathologic, and molecular information, using a scientific methodology for predictive factor selection and weight assessment.

Evaluating the diagnostic efficacy of whole-body MRI versus 123I-mIBG/131I-mIBG imaging in metastatic pheochromocytoma and paraganglioma

This study aimed to compare tumor lesion detectability and diagnostic accuracy of whole-body magnetic resonance imaging (WB-MRI) and radioiodine-labeled meta-iodo-benzylguanidine (mIBG) imaging techniques in patients with metastatic pheochromocytoma and paraganglioma (PPGL). This retrospective study included 13 patients had pheochromocytoma and 5 had paraganglioma, who were all suspected of having metastatic tumors. Each patient underwent WB-MRI and 123I-mIBG as a pretreatment screening for 131I-mIBG therapy. Two expert reviewers evaluated WB-MRI, 123I-mIBG images, and post-therapy 131I-mIBG images for the presence of metastatic lesions in the lungs, bones, liver, lymph nodes, and other organs. Diagnostic measures for detecting metastatic lesions, including sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV), and receiver operating characteristics (ROC)-area under the curve (AUC), were calculated for each imaging technique. We analyzed WB-MRI images for detecting metastatic lesions, which demonstrated sensitivity, specificity, accuracy, PPV, NPV, and AUC of 82%, 97%, 90%, 96%, 86%, and 0.92, respectively. These values were 83%, 95%, 89%, 94%, 86%, and 0.90 in 123I-mIBG images and 85%, 92%, 89%, 91%, 87%, and 0.91 in post-therapy 131I-mIBG images, respectively. Our results reveal the comparable diagnostic accuracy of WB-MRI to one of the mIBG images.

Pheochromocytoma. Preoperative approach

Pheochromocytomas are rare neuroendocrine tumors that derive from the chromaffin cells of the adrenal medulla and secrete catecholamines. The measurement of plasma or fractionated urine metanephrines is the hormonal determination of choice for the biochemical diagnosis. Once the biochemical diagnosis is confirmed, the next step is the localization study. It is recommended to request a genetic study in all patients with pheochromocytomas since 40% of cases are hereditary. Once the diagnostic study is completed, preoperative treatment with alpha blockers should be instituted at least 7-14 days before adrenalectomy. However, in low-risk patients, the omission of presurgical treatment could be considered if the surgery is performed in centers with experience and a strict monitoring of the patient is carried out during the perioperative period. This document offers a practical guide on the diagnosis and perioperative approach in patients with pheochromocytomas.

Automated online solid-phase extraction-tandem mass spectrometry detection for simultaneous analysis of acidic and alkaline catecholamines and their metabolites in human urine

Metabolic dysregulation of catecholamines (CAs) is implicated in various human diseases. Simultaneously analyzing these acidic and alkaline CAs and their metabolites poses a significant challenge for clinical detection. This study introduces an efficient method employing automated online solid-phase extraction coupled with tandem mass spectrometry (aoSPE-MS/MS). The method employs weak cation exchange (WCX) and mixed-mode anion exchange (MAX) adsorbents to fabricate an on-line solid-phase extraction (SPE) column, along with an automated injection and multi-valve switching capabilities. The setup allows for automated extraction and analysis of urine samples in 15 minutes while retaining a wide range of acidic and basic CAs and their metabolites. The applicability of this method was demonstrated by optimising the adsorbent dosage volume, extraction solvent, and extraction rate. The limits of detection (LODs) and limits of quantitation (LOQs) for the 8 CAs and their metabolites were determined using the aoSPE-MS/MS approach, with ranges of 0.0625 ∼ 62.5 ng/mL and 0.125 ∼ 125 ng/mL, respectively. Additionally, assessments were made on the linearity, accuracy, and precision within and between batches, as well as matrix and ionic effects, and spiked recoveries. The study discovered that the aoSPE-MS/MS technique simplifies operation, increases efficiency, saves time, and has low detection and quantification limits when detecting a wide range of acid and alkaline CAs and their metabolites in urine. The study successfully demonstrated the high-throughput and automated detection of the 8 CAs and their metabolites with varying acidity and alkalinity in human urine samples. This method is expected to be a potential powerful tool for clinical detection.

A novel strategy for predicting the efficacy of temozolomide treatment for metastatic pheochromocytomas/paragangliomas

BACKGROUND

There are few studies on the efficacy of temozolomide (TMZ) in the treatment of Metastatic pheochromocytoma / paraganglioma (MPP) patients. And it remains unclear which MPP patients may benefit from TMZ treatment.

METHODS

This was a prospective study. MPP patients were enrolled. Patients were treated with TMZ until disease progression or intolerable toxicities. The primary endpoints were disease control rate (DCR) and objective response rate (ORR). Secondary endpoints included biochemical response rate progression-free survival (PFS) and safety. We compared the difference between effective and ineffective groups, to explore which patients are more suitable for TMZ treatment.

RESULTS

62 patients with MPP were enrolled and tumor response were evaluated in 54 patients. The DCR was 83% (35/42), and the ORR was 24% (10/41) among the progressive patients. PFS was 25.2 ± 3.1 months. The most common adverse event was nausea (41/55). We found that 92.9% (13/14) of patients with MGMT methylation greater than 7% respond to treatment. For the patients with MGMT methylation less than 7%, Ki-67 index could be used to guide the use of TMZ in these patients. Among the patients with Ki-67 index less than 5%, 66% (8/12) patients showed respond to treatment, and only 33% (4/12) patients with Ki-67 index more than 5% showed respond to TMZ.

CONCLUSIONS

This study indicated that TMZ is a potential choice for the treatment of MPP with the high ability on disease control and well tolerability. We recommended to MGMT methylation analysis test and Ki-67 index to guide TMZ application.

[Paragangliomas of the head and neck]

Paragangliomas represent a heterogeneous group of rare neuroendocrine tumors with marked variability in symptoms and disease course. Due to the close proximity to neurovascular structures, paragangliomas of the head and neck region can cause a variety of symptoms. To this day, there are no reliable prognostic factors that can predict a potentially malignant course. All patients with newly diagnosed paragangliomas should undergo an early diagnostic workup and regular follow-up examinations in specialized centers. While radical resection was previously regarded as standard treatment for paragangliomas, radiotherapy and active surveillance (watch-and-scan strategy) have become equally important over the years. Low-threshold techniques for molecular pathology analysis of the mutation-specific behavior of paragangliomas are nowadays available.

[A rare case of recurrent myocarditis revealing pheochromocytoma]

Pheochromocytoma is a rare neuroendocrine tumor characterized by overproduction of catecholamines. The overproduction of catecholamines leads to cardiac remodeling which manifests in several forms ranging from Takotsubo to dilated cardiomyopathy. Studies suggest that pheochromocytoma-induced cardiomyopathy can take various forms depending on the duration of catecholamine exposure. Myocarditis is a fairly rare presentation of cardiac manifestations of pheochromocytoma which are mainly dominated by Takotsubo and dilated cardiomyopathies. We report a rare case of recurrent myocarditis in a young 37-year-old patient revealing the diagnosis of adrenal pheochromocytoma. Through this case and through a review of the literature we will take stock of the epidemiology of cardiac involvement in pheochromocytoma, mainly cardiomyopathies, and we will take stock of the value of diagnosis and early management in improving the prognosis of patients.

Head-to-head comparison between [68Ga]Ga-DOTA-NOC and [18F]DOPA PET/CT in a diverse cohort of patients with pheochromocytomas and paragangliomas

PURPOSE

To compare the detection ability of 68Ga-labelled DOTA-l-Nal3-octreotide ([68Ga]Ga-DOTA-NOC) and 6-[18F]fluoro-L-3,4-dihydroxyphenylalanine ([18F]DOPA) in patients with phaeochromocytomas and paragangliomas (PPGLs) of different origins and gene mutations, such as germline succinate dehydrogenase complex genes (SDHx).

METHODS

Eighty-five patients with histopathologically confirmed PPGLs who underwent both [68Ga]Ga-DOTA-NOC and [18F]DOPA PET/CT from March 2017 to June 2023 were enrolled in this retrospective study. For comparative analyses, PPGLs were classified as phaeochromocytoma (PCC), sympathetic paraganglioma (sPGL), and head/neck paraganglioma (HNPGL). Detection rates were analyzed on per-patient and per-lesion bases and compared using the Chi-square/Fischer's exact test.

RESULTS

Among 85 patients with PPGLs (48 males; 43 years ± 17 [SD]), the patient-based detection rates of [68Ga]Ga-DOTA-NOC and [18F]DOPA PET/CT were 87.1% (74/85) and 89.4% (76/85), respectively (p = 0.634), and the lesion-based detection rates were 80.8% (479/593) and 71.2% (422/593), respectively (p < 0.001). Only one patient with a recurrent PCC presented double-negative imaging, while 66 patients exhibited double-positive imaging. The remaining patients were either [68Ga]Ga-DOTA-NOC-negative/[18F]DOPA-positive (n = 10) or [68Ga]Ga-DOTA-NOC-positive/[18F]DOPA-negative (n = 8). In subgroup analyses, [68Ga]Ga-DOTA-NOC PET/CT detected significantly more metastases of sPGL (91.1%, 236/259) and SDHx-related PPGL (89.6%, 86/96) than [18F]DOPA PET/CT (48.6%[126/259] and 50.0%[48/96], respectively; both p < 0.001). However, [18F]DOPA showed significantly higher detection rates of PCC in both primary/recurrent and metastatic lesions (94.3%[50/53] vs. 62.3%[33/53] and 87.9%[174/198] vs. 69.2%[137/198], respectively; both p < 0.001). Regarding metastases in different organs, [68Ga]Ga-DOTA-NOC PET/CT detected more lesions than [18F]DOPA PET/CT in bone (96.2%[176/183] vs. 66.1%[121/183]; p < 0.001) and lymph nodes (82.0%[73/89] vs. 53.9%[48/89]; p < 0.001) but less lesions in peritoneum (20%[4/20] vs. 100%[20/20]; p < 0.001).

CONCLUSION

[68Ga]Ga-DOTA-NOC and [18F]DOPA are complementary in diagnosing PPGL under the appropriate clinical setting. [68Ga]Ga-DOTA-NOC should be considered as the ideal first-line tracer for detecting metastases of sPGL and SDHx-related tumours, whereas [18F]DOPA may be the optimal tracer for evaluating non-SDHx-related PCC, especially in detecting primary lesions and monitoring recurrence.

A comparative analysis of surgically excised hereditary and sporadic pheochromocytomas: Insights from a single-center experience

Pheochromocytoma is a tumor that usually originating from adrenal medullary chromaffin cells and producing one or more catecholamines, can manifest as hereditary or sporadic. While the majority pheochromocytomas are sporadic, hereditary forms are often associated with genetic syndromes such as von Hippel-Lindau, multiple endocrine neoplasia type 2, and neurofibromatosis type 1. This study aims to analyze data from our series of surgically excited pheochromocytoma patients and compare the characteristics between hereditary and sporadic cases. We retrospectively evaluated 33 diagnosed pheochromocytoma patients, documenting clinical features, surgical complications, and tumor characteristics in both hereditary and sporadic cases. Among the patients, 21% (7 individuals) had hereditary pheochromocytoma, while 79% (26 individuals) had sporadic cases. During diagnosis, hereditary pheochromocytoma patients exhibited a significantly lower mean age compared to the sporadic group (26.4 ± 9.9 years vs. 50.4 ± 14.0 years; p < 0.001). The maximum tumor size was also lower in hereditary cases compared to sporadic cases (p = 0.004). Adrenal tumor localization analysis showed that 63.6% were right-sided, 24.2% were left-sided, and 12.1% were bilateral. Laboratory analysis revealed significantly higher urinary norepinephrine levels in hereditary pheochromocytoma patients (p = 0.021). Our findings suggest that hereditary pheochromocytoma cases are characterized by a younger age at diagnosis, smaller tumor size, and a higher prevalence of multiple bilateral adrenal adenomas. We recommend genetic testing for all pheochromocytoma patients, particularly those with early-onset disease and bilateral adrenal tumors.

Clinical Significance of Pheochromocytoma Size on the Timing and Extent of Surgery

INTRODUCTION

Elevated metanephrine and catecholamine levels 3-fold upper limit of normal (ULN) are diagnostic for pheochromocytoma. We sought to determine whether size correlates with biochemical activity or symptoms which could guide timing of surgery.

METHODS

Data from consecutive patients undergoing adrenalectomy for pheochromocytoma at our institution over a 10-year period were retrospectively collected. These included maximal lesion diameter on preoperative imaging, plasma/urine metanephrine and/or catecholamine levels, demographic variables and presence of typical paroxysmal symptoms. Receiver operating characteristic curves were used to assess predictive accuracy.

RESULTS

Sixty-three patients were included in the analysis (41 females and 22 males). Median age was 56 (43, 69) years. Due to various referring practices, 31 patients had documented 24-h urine metanephrine, 26 had 24-h urine catecholamine, and 52 had fractionated plasma metanephrine levels available for review. Values were converted to fold change compared to ULN and the maximum of all measured values was used for logistic regression. Median tumor size was 3.40 (2.25, 4.55) cm in greatest dimension. Tumor size at which pheochromocytoma produced > 3-fold ULN was ≥2.3 cm (AUC of 0.84). Biochemical activity increased with doubling tumor size (odds ratio = 8, P = 0.0004) or ≥ 1 cm increase in tumor size (odds ratio = 3.03, P = 0.001). 40 patients had paroxysmal symptoms, but there was no significant correlation between tumor size/biochemical activity and symptoms.

CONCLUSIONS

In our study, tumor size directly correlated with the degree of biochemical activity and pheochromocytomas ≥2.3 cm produced levels 3 times ULN. These findings may allow clinicians to adjust timing of operative intervention.

Computed tomography-guided percutaneous cryoablation of hereditary adrenal pheochromocytoma in three patients

OBJECTIVES

Pheochromocytomas (PHEO) are neuroendocrine tumors rarely diagnosed in children. We are reporting on the management challenges of three adolescent patients who present with hereditary PHEO.

CASE PRESENTATION

The index patient and his male sibling presented with bilateral PHEO, while a third patient presented with a unilateral PHEO, all associated with von Hippel-Lindau (VHL) syndrome. The patients were treated with computed tomography (CT)-guided percutaneous cryoablation (CRA) of the adrenal lesions, with varying degrees of success.

CONCLUSIONS

CT-guided percutaneous CRA of hereditary PHEO has not been reported in the pediatric population and may represent a novel treatment strategy that reduces the risk of intraprocedural complications and adrenal insufficiency (AI).

Two sisters diagnosed with familial paraganglioma syndrome type 1 (FPGL1) and multiple endocrine neoplasia type 2A (MEN2A)

BACKGROUND

In clinical practice, genetic testing has become standard for many cancerous diseases. While a diagnosis of a single hereditary syndrome is not uncommon, the coexistence of two genetic diseases, even with partially common symptoms, remains unusual. Therefore, targeted next-generation sequencing (NGS), along with genetic consultation and imaging studies, is essential for every patient with confirmed paraganglioma. In this report, we present two sisters diagnosed with multiple endocrine neoplasia type 2 (MEN2A) and familial paraganglioma syndrome type 1 (FPGL1).

CASE PRESENTATION

After presenting to the clinic with neck tumors persisting for several months, both patients underwent tumor removal procedures following imaging and laboratory studies. Pathological reports confirmed the diagnosis of paragangliomas. Subsequently, genetic testing, including NGS, revealed a mutation in the rearranged during transfection (RET) gene: the heterozygous change (c.2410G > A), (p.Val804Met), and a variant of the succinate dehydrogenase complex subunit D (SDHD) gene: (c.64 C > T), (p.Arg22Ter). Subsequently, thyroidectomy procedures were scheduled in both cases.

CONCLUSION

To the best of our knowledge, this is the first report presenting these two mutations in two related patients, resulting in distinctive genetic syndromes with similar manifestations. This underscores that although infrequent, multiple hereditary disorders may co-occur in the same individual.

Identification of Predictors of Metastatic Potential in Paragangliomas to Develop a Prognostic Score (PSPGL)

Context

Paragangliomas (PGLs) are rare tumors in adrenal and extra-adrenal locations. Metastasis are found in approximately 5% to 35% of PGLs, and there are no reliable predictors of metastatic disease.

Objective

This work aimed to develop a prognostic score of metastatic potential in PGLs.

Methods

A retrospective analysis was conducted of clinical data from a cohort with PGLs and tumor histological assessment. Patients were divided into metastatic PGL (presence of metastasis) and nonmetastatic PGL (absence of metastasis ≥96 months of follow-up) groups. Univariate and multivariable analysis were performed to identify predictors of metastatic potential. A prognostic score was developed based on coefficients of multivariable analysis. Kaplan-Meier curves were generated to estimate disease-specific survival (DSS).

Results

Out of 263 patients, 35 patients had metastatic PGL and 110 patients had nonmetastatic PGL. In multivariable analysis, 4 features were independently related to metastatic disease and composed the Prognostic Score of Paragangliomas (PSPGL): presence of central or confluent necrosis (33 points), more than 3 mitosis/10 high-power field (HPF) (28 points), extension into adipose tissue (20 points), and extra-adrenal location (19 points). A PSPGL of 24 or greater showed similar sensitivity with higher specificity than the Pheochromocytoma of the Adrenal Gland Scaled Score (PASS) and Grading System for Adrenal Pheochromocytoma and Paraganglioma (GAPP). PSPGL less than or equal to 20 was associated with a risk of metastasis of approximately 10%, whereas a PSPGL of 40 or greater was associated with approximately 80%. The presence of metastasis and Ki-67 of 3% or greater were related to lower DSS.

Conclusion

The PSPGL, composed of 4 easy-to-assess parameters, demonstrated good performance in predicting metastatic potential and good ability in estimating metastasis risk.

Selection of Germline Genetic Testing Panels in Patients With Cancer: ASCO Guideline

PURPOSE

To guide use of multigene panels for germline genetic testing for patients with cancer.

METHODS

An ASCO Expert Panel convened to develop recommendations on the basis of a systematic review of guidelines, consensus statements, and studies of germline and somatic genetic testing.

RESULTS

Fifty-two guidelines and consensus statements met eligibility criteria for the primary search; 14 studies were identified for Clinical Question 4.

RECOMMENDATIONS

Patients should have a family history taken and recorded that includes details of cancers in first- and second-degree relatives and the patient's ethnicity. When more than one gene is relevant based on personal and/or family history, multigene panel testing should be offered. When considering what genes to include in the panel, the minimal panel should include the more strongly recommended genes from Table 1 and may include those less strongly recommended. A broader panel may be ordered when the potential benefits are clearly identified, and the potential harms from uncertain results should be mitigated. Patients who meet criteria for germline genetic testing should be offered germline testing regardless of results from tumor testing. Patients who would not normally be offered germline genetic testing based on personal and/or family history criteria but who have a pathogenic or likely pathogenic variant identified by tumor testing in a gene listed in Table 2 under the outlined circumstances should be offered germline testing.Additional information is available at www.asco.org/molecular-testing-and-biomarkers-guidelines.

Radio theranostics in paragangliomas and pheochromocytomas

This continuing education aims to present in a clear and easy-to-understand manner the biology of paragangliomas and pheochromocytomas (PPGLs), the functional imaging studies available for their diagnosis and therapeutic planning, the requirements necessary to administer radioligand therapy (RLT) and the characteristics of these treatments (inclusion criteria, administration protocols, adverse effects and future perspectives). In this pathology we have two RLT options: [131I]MIBG and [177Lu]Lu-DOTA-TATE. The indication for treatment is determined by the expression of its therapeutic target in functional imaging studies, allowing precision and personalized medicine. Although most of the results we have for both treatments have as origin small retrospective series, RLT is presented as a safe and well-tolerated therapeutic option in PPGLs with slow-moderate progression or with uncontrollable symptoms, obtaining high disease control rates.

Imaging of Pheochromocytomas and Paragangliomas

Pheochromocytomas/paragangliomas are unique in their highly variable molecular landscape driven by genetic alterations, either germline or somatic. These mutations translate into different clusters with distinct tumor locations, biochemical/metabolomic features, tumor cell characteristics (eg, receptors, transporters), and disease course. Such tumor heterogeneity calls for different imaging strategies in order to provide proper diagnosis and follow-up. This also warrants selection of the most appropriate and locally available imaging modalities tailored to an individual patient based on consideration of many relevant factors including age, (anticipated) tumor location(s), size, and multifocality, underlying genotype, biochemical phenotype, chance of metastases, as well as the patient's personal preference and treatment goals. Anatomical imaging using computed tomography and magnetic resonance imaging and functional imaging using positron emission tomography and single photon emission computed tomography are currently a cornerstone in the evaluation of patients with pheochromocytomas/paragangliomas. In modern nuclear medicine practice, a multitude of radionuclides with relevance to diagnostic work-up and treatment planning (theranostics) is available, including radiolabeled metaiodobenzylguanidine, fluorodeoxyglucose, fluorodihydroxyphenylalanine, and somatostatin analogues. This review amalgamates up-to-date imaging guidelines, expert opinions, and recent discoveries. Based on the rich toolbox for anatomical and functional imaging that is currently available, we aim to define a customized approach in patients with (suspected) pheochromocytomas/paragangliomas from a practical clinical perspective. We provide imaging algorithms for different starting points for initial diagnostic work-up and course of the disease, including adrenal incidentaloma, established biochemical diagnosis, postsurgical follow-up, tumor screening in pathogenic variant carriers, staging and restaging of metastatic disease, theranostics, and response monitoring.

Pediatric hypertension as an early manifestation of cardiovascular disease in children

In adults, cardiovascular events associated with arterial hypertension (AH) have a major impact on morbidity and mortality. In light of recent findings, AH in children has been interpreted as early cardiovascular disease (CVD), while exposure to CV risk factors in children proves to be a predictor of subclinical CVD in adults. The American College of Cardiology/American Heart Association has recently updated the classifications for measuring blood pressure (BP) in adults and children. Primary AH in children is generally asymptomatic, and it is associated with a family history of AH, overweight/obesity, and normal morphofunctional characteristics of the urinary system. The younger the child and the higher the BP, the greater the likelihood of secondary AH. The investigation into the etiology of AH begins with a detailed anamnesis, which should include clinical information and details on the use of medication, smoking, and alcohol consumption from the perinatal period to the time of consultation. Modifying risk factors by reducing weight, decreasing alcohol consumption and increasing vegetable intake from childhood to adulthood has been associated with the resolution of AH in the childhood-adulthood transition, and with the reversal of cardiometabolic adverse effects in non-obese adult individuals. Pharmacological therapy should be initiated in cases of symptomatic AH, AH secondary to chronic kidney disease or diabetes mellitus, presence of target organ lesions, stage 2 AH with no modifiable cause and resistant AH unresponsive to lifestyle changes.

Clinical management and outcome of head and neck paragangliomas (HNPGLs): A single centre retrospective study

CONTEXT

Head and neck paragangliomas (HNPGLs) are rare, usually benign, slow-growing tumours arising from neural crest-derived tissue. Definitive management pathways for HNPGLs have yet to be clearly defined.

OBJECTIVE

To review our experience of the clinical features and management of these tumours and to analyse outcomes of different treatment modalities.

METHODS

Demographic and clinical data were obtained from The Northern Ireland Electronic Care Record (NIECR) as well from a prospectively maintained HNPGL database between January 2011 through December 2023.

RESULTS

There were 87 patients; 50 females: 37 males with a mean age of 52.3 ± 14.2 years old (range 17-91 years old). 58.6% (n = 51) of patients had carotid body tumours, 25.2% (n = 22) glomus vagal tumours, 6.8% (n = 6) tumours in the middle ear, 2.2% (n = 2) in the parapharyngeal space and 1.1% (n = 1) in the sphenoid sinus. 5.7% (n = 5) of patients had multifocal disease. The mean tumour size at presentation was 3.2 ± 1.4 cm (range 0.5-6.9 cm). Pathogenic SDHD mutations were identified in 41.3% (n = 36), SDHB in 12.6% (n = 11), SDHC in 2.2% (n = 2) and SDHA in 1.1% (n = 1) of the patients. Overall treatment modalities included surgery alone in 51.7% (n = 45) of patients, radiotherapy in 14.9% (n = 13), observation in 28.7% (n = 25), and somatostatin analogue therapy with octreotide in 4.5% (n = 4) of patients. Factors associated with a significantly higher risk of recurrence included age over 60 years (p = .04), tumour size exceeding 2 cm (p = .03), positive SDHx variants (p = .01), and vagal and jugular tumours (p = .04).

CONCLUSION

The majority of our patients underwent initial surgical intervention and achieved disease stability. Our results suggest that carefully selected asymptomatic or medically unfit patients can be safely observed provided lifelong surveillance is maintained. We advocate for the establishment of a UK and Ireland national HNPGL registry, to delineate optimal management strategies for these rare tumours and improve long term outcomes.

Novel alternative tools for metastatic pheochromocytomas/paragangliomas prediction

OBJECTIVE

The existing prediction models for metastasis in pheochromocytomas/paragangliomas (PPGLs) showed high heterogeneity in different centers. Therefore, this study aimed to establish new prediction models integrating multiple variables based on different algorithms.

DESIGN AND METHODS

Data of patients with PPGLs undergoing surgical resection at the Peking Union Medical College Hospital from 2007 to 2022 were collected retrospectively. Patients were randomly divided into the training and testing sets in a ratio of 7:3. Subsequently, decision trees, random forest, and logistic models were constructed for metastasis prediction with the training set and Cox models for metastasis-free survival (MFS) prediction with the total population. Additionally, Ki-67 index and tumor size were transformed into categorical variables for adjusting models. The testing set was used to assess the discrimination and calibration of models and the optimal models were visualized as nomograms. Clinical characteristics and MFS were compared between patients with and without risk factors.

RESULTS

A total of 198 patients with 59 cases of metastasis were included and classified into the training set (n = 138) and testing set (n = 60). Among all models, the logistic regression model showed the best discrimination for metastasis prediction with an AUC of 0.891 (95% CI, 0.793-0.990), integrating SDHB germline mutations [OR: 96.72 (95% CI, 16.61-940.79)], S-100 (-) [OR: 11.22 (95% CI, 3.04-58.51)], ATRX (-) [OR: 8.42 (95% CI, 2.73-29.24)] and Ki-67 ≥ 3% [OR: 7.98 (95% CI, 2.27-32.24)] evaluated through immunohistochemistry (IHC), and tumor size ≥ 5 cm [OR: 4.59 (95% CI, 1.34-19.13)]. The multivariate Cox model including the above risk factors also showed a high C-index of 0.860 (95% CI, 0.810-0.911) in predicting MFS after surgery. Furthermore, patients with the above risk factors showed a significantly poorer MFS (P ≤ 0.001).

CONCLUSIONS

Models established in this study provided alternative and reliable tools for clinicians to predict PPGLs patients' metastasis and MFS. More importantly, this study revealed for the first time that IHC of ATRX could act as an independent predictor of metastasis in PPGLs.

Increasing Catecholamine Secretion Through NPY in Pheochromocytomas With False-Negative 123 I-MIBG Scintigraphy

INTRODUCTION

123 I-MIBG has been well established as a functional imaging tool, and 131 I-MIBG therapy is being considered for catecholamine-secreting tumors. Tumors with the characteristics of a noradrenergic biochemical phenotype, small, malignant, metastatic, extra-adrenal, bilateral, and hereditary, especially SDHx -related tumors, are reported to correlate with reduced MIBG uptake. However, the potential molecular mechanisms influencing MIBG uptake have been poorly studied.

PATIENTS AND METHODS

To identify critical genes that may enhance MIBG accumulation in pheochromocytomas (PCCs), we performed RNA-seq analyses for 16 operated patients with PCCs (6 MIBG-negative and 10 MIBG-positive) combined with RT-qPCR for 27 PCCs (5 MIBG-negative and 22 MIBG-positive) and examined primary cultures of the surgical tissues.

RESULTS

In the present study, 6 adrenal nodules of 66 nodules surgically removed from 63 patients with PCCs (9%) were MIBG negative. MIBG, a guanethidine analog of norepinephrine, can enter chromaffin cells through active uptake via the cellular membrane, be deposited in chromaffin granules, and be released via Ca 2+ -triggered exocytosis from adrenal chromaffin cells. When we compared expression of several catecholamine biosynthesis and secretion-associated genes between MIBG-negative and MIBG-positive tumors using transcriptome analyses, we found that neuropeptide Y, which is contained in chromaffin granules, was significantly increased in MIBG-negative tumors. NPY stimulated norepinephrine secretion dose-dependently in primary cell culture derived from MIBG-positive PCC. In our study, MIBG-negative PCCs were all norepinephrine-hypersecreting tumors.

CONCLUSIONS

These data indicate that NPY upregulation in PCCs may stimulate chromaffin granule catecholamine secretion, which is associated with false-negative 123 I-MIBG scintigraphy.

CT-based radiomics research for discriminating the risk stratification of pheochromocytoma using different machine learning models: a multi-center study

OBJECTIVES

The purpose of this study was to explore and verify the value of various machine learning models in preoperative risk stratification of pheochromocytoma.

METHODS

A total of 155 patients diagnosed with pheochromocytoma through surgical pathology were included in this research (training cohort: n = 105; test cohort: n = 50); the risk stratification scoring system classified a PASS score of < 4 as low risk and a PASS score of ≥ 4 as high risk. From CT images captured during the non-enhanced, arterial, and portal venous phase, radiomic features were extracted. After reducing dimensions and selecting features, Logistic Regression (LR), Extra Trees, and K-Nearest Neighbor (KNN) were utilized to construct the radiomics models. By adopting ROC curve analysis, the optimal radiomics model was selected. Univariate and multivariate logistic regression analyses of clinical radiological features were used to determine the variables and establish a clinical model. The integration of radiomics and clinical features resulted in the creation of a combined model. ROC curve analysis was used to evaluate the performance of the model, while decision curve analysis (DCA) was employed to assess its clinical value.

RESULTS

3591 radiomics features were extracted from the region of interest in unenhanced and dual-phase (arterial and portal venous phase) CT images. 13 radiomics features were deemed to be valuable. The LR model demonstrated the highest prediction efficiency and robustness among the tested radiomics models, with an AUC of 0.877 in the training cohort and 0.857 in the test cohort. Ultimately, the composite of clinical features was utilized to formulate the clinical model. The combined model demonstrated the best discriminative ability (AUC, training cohort: 0.887; test cohort: 0.874). The DCA of the combined model showed the best clinical efficacy.

CONCLUSION

The combined model integrating radiomics and clinical features had an outstanding performance in differentiating the risk of pheochromocytoma and could offer a non-intrusive and effective approach for making clinical decisions.

Cabozantinib in patients with unresectable and progressive metastatic phaeochromocytoma or paraganglioma (the Natalie Trial): a single-arm, phase 2 trial

BACKGROUND

Metastatic phaeochromocytomas and paragangliomas (MPPGs) are orphan diseases. Up to 50% of MPPGs are associated with germline pathogenic variants of the SDHB gene. These tumours and many non-familial MPPGs exhibit a phenotype that is characterised by abnormal angiogenesis. We aimed to assess the activity and safety of cabozantinib, an antiangiogenic multi-tyrosine kinase inhibitor, in patients with MPPGs.

METHODS

The Natalie Trial is a single-arm, phase 2 clinical trial being conducted at The University of Texas MD Anderson Cancer Center (Houston, TX, USA). Patients aged 18 years or older with histologically confirmed, progressive, and unresectable MPPGs, with an Eastern Cooperative Oncology Group performance status of 0-2, were treated with oral cabozantinib 60 mg/day. The primary endpoint was the investigator-assessed overall response rate per the Response Evaluation Criteria in Solid Tumours version 1.1 criteria. All outcomes were assessed in all evaluable participants who received any amount of study treatment. The trial is registered with ClinicalTrials.gov (NCT02302833) and is active but not recruiting.

FINDINGS

From March 10, 2015, to May 11, 2021, 17 patients (13 male participants and four female participants) were enrolled. The median follow-up was 25 months (IQR 18-49). The overall response rate was 25·0% (95% CI 7·3-52·4; four of 16 patients). Seven grade 3 adverse events were reported in six patients, including single cases of hand-and-foot syndrome, hypertension, rectal fistula, QT prolongation, and asymptomatic hypomagnesaemia, and two cases of asymptomatic elevations of amylase and lipase. There were no grade 4 adverse events and no patient died on-study.

INTERPRETATION

Cabozantinib shows promising activity in patients with MPPGs.

FUNDING

Team NAT Foundation, Margaret Cazalot, and Clarence P Cazalot.

Theranostics in Neuroendocrine Tumors

ABSTRACT

Neuroendocrine tumors (NETs) are rare tumors that develop from cells of the neuroendocrine system and can originate in multiple organs and tissues such as the bowels, pancreas, adrenal glands, ganglia, thyroid, and lungs. This review will focus on gastroenteropancreatic NETs (more commonly called NETs) characterized by frequent somatostatin receptor (SSTR) overexpression and pheochromocytomas/paragangliomas (PPGLs), which typically overexpress norepinephrine transporter. Advancements in SSTR-targeted imaging and treatment have revolutionized the management of patients with NETs. This comprehensive review delves into the current practice, discussing the use of the various Food and Drug Administration-approved SSTR-agonist positron emission tomography tracers and the predictive imaging biomarkers, and elaborating on 177Lu-DOTATATE peptide receptor radionuclide therapy including the evolving areas of posttherapy imaging practices and peptide receptor radionuclide therapy retreatment. SSTR-targeted imaging and therapy can also be used in patients with PPGL; however, this patient population has demonstrated the best outcomes from norepinephrine transporter-targeted therapy with 131I-metaiodobenzylguanidine. Metaiodobenzylguanidine theranostics for PPGL will be discussed, noting that in 2024 it became commercially unavailable in the United States. Therefore, the use and reported success of SSTR theranostics for PPGL will also be explored.

Recurrent Pheochromocytoma With Bone Metastasis Eight Years After Bilateral Adrenalectomies in a Patient With Neurofibromatosis Type 1

Background/Objective

Pheochromocytoma can recur years after curative surgical resection. Rarely, it may reoccur as metastasis. Here, we present a case of metastatic pheochromocytoma to the bones in a patient with neurofibromatosis type 1 (NF1), 8 years after initial resection of primary bilateral adrenal pheochromocytomas without metastases.

Case Report

A 44-year-old woman presented with diffuse body pain and palpitations. Her past medical history included NF1 and hypertension. Eight years prior to her current presentation, she had undergone a bilateral adrenalectomy for the management of bilateral adrenal pheochromocytomas. Her plasma metanephrines normalized after surgery and remained normal at her 1-year postoperative visit. She was subsequently lost to follow-up until her current presentation. Our evaluation revealed significantly elevated urine and plasma metanephrines as well as innumerable DOTATATE avid lesions along the axial and perpendicular spine compatible with a metastatic neuroendocrine tumor. She was started on doxazosin and metoprolol and discharged home with a plan to be seen by Oncology to discuss systemic therapy.

Discussion

Predicting malignant disease in patients with primary tumors without metastases is challenging. There is no single factor that can reliably predict tumor behavior. It is unknown if individuals with NF1, who have a genetic predisposition for developing pheochromocytomas, are at an increased risk of malignant disease.

Conclusion

Due to a lack of accurate predictors, annual biochemical testing is recommended after primary tumor resection and in patients with a genetic predisposition. Strict lifelong follow-up should be strongly considered due to a possible higher risk of malignant disease.

The combination of doxazosin and metyrosine as a preoperative treatment for pheochromocytomas and paragangliomas

PURPOSE

Preoperative medical management is critical to prevent intraoperative cardiovascular complications in patients with pheochromocytomas and paragangliomas (PPGLs). Initial treatment involves α-adrenergic receptor blockers. However, while the routine use of metyrosine alongside these blockers is not strongly recommended due to a lack of evidence supporting its efficacy and associated safety concerns, there are previous studies on combination therapy with phenoxybenzamine and metyrosine. There are few reports on combination therapy with the selective α1-adrenergic receptor blocker doxazosin. Therefore, we investigated this combination treatment, which theoretically can affect perioperative outcomes in patients with PPGLs. To our knowledge, this is the first such study.

METHODS

This retrospective single-center observational study involved 51 patients who underwent surgical resection of PPGLs at Kobe University Hospital between 2014 and 2022. All patients received doxazosin at maximum doses. Fourteen patients received concomitant metyrosine, while 37 received doxazosin alone. Their perioperative outcomes were compared.

RESULTS

No severe event, such as acute coronary syndrome, was observed in either group. Intraoperatively, the doxazosin + metyrosine group exhibited a lower median minimum systolic blood pressure (56 [54-60] vs. 68 [59-74] mmHg, P = 0.03) and required lower median remifentanil (P = 0.04) and diltiazem (P = 0.02) doses than the doxazosin-alone group.

CONCLUSION

The combination of metyrosine and doxazosin as a preoperative treatment for PPGLs affects intraoperative circulatory hemodynamics, such as a reduced occurrence of blood pressure elevation during surgery. Further research is necessary to identify patients who will benefit most from this combination treatment.

Head and Neck Malignant Paragangliomas: Experience from a Single Institution

Objectives: To summarize the clinicopathological and genetic features of malignant paragangliomas in head and neck cancer and to explore the appropriate treatment options for this rare lesion. Methods: Six patients harboring head and neck malignant paraganglioma from Beijing Tongren Hospital were retrospectively reviewed. The clinicopathological characteristics, gene mutations, and prognosis of these patients were analyzed. Results: Of these 6 patients, 3 were male and 3 were female; 4 patients harbored malignant carotid body tumors, and two had malignant vagal paragangliomas. Three patients had cervical lymph node metastasis, two presented with lung and bone metastasis, and 1 had lung and liver metastasis. Of the 6 patients, four underwent surgical resection, and the other two patients denied surgery and instead received chemotherapy with paclitaxel, ifosfamide, and dacarbazine. These 2 patients with vagal paraganglioma received postoperative radiotherapy. All 6 patients are still alive at the present time, with a median follow-up time of 66 months. Positive Ki-67 expression in tumor tissue ranged from 1% to 40%. Genetic mutations in SDHD, SDHB, ATR, and MAP3K13 were identified in 4 patients. Conclusions: After comprehensive treatment, head and neck malignant paraganglioma can attain a favorable prognosis. Genetic mutations are commonly detected in patients with malignant paragangliomas. This study also identified mutations in ATR and MAP3K13 in these patients.

Endoscopic transcanal coblation excision of glomus tympanicum: a novel technique

OBJECTIVE

To evaluate the feasibility of coblation in excision of glomus tympanicum tumors.

PATIENTS AND METHODS

A retrospective study carried out over 28 patients with types I and II glomus tympanicum tumors according to GLASSCOCK-JACKSON classification. Preoperative radiological and endocrinal evaluation were performed. All patients underwent endoscopic transcanal excision of their glomus tympanicum tumors using coblation.

RESULTS

None of the patients developed recurrence during the 1-year follow up period proved radiologically. None of the patients developed facial palsy postoperatively. Differences between preoperative and postoperative dizziness and taste disturbance were statistically non-significant. Tinnitus disappeared completely in 22 patients postoperatively. A statistically significant reduction in Tinnitus Handicap Inventory (THI) after surgery was found. Statistically significant reductions in postoperative air conduction (AC) threshold and air bone gap (ABG) were recorded while bone conduction (BC) threshold showed statistically non-significant change.

CONCLUSION

Coblation is an effective and safe tool in excision of glomus tympanicum tumors. Further studies comparing coblation with laser and piezosurgery are strongly recommended.

Seventy years of pheochromocytomas and paragangliomas in Argentina. The FRENAR database

Pheochromocytomas and paragangliomas (PPGL) are neuroendocrine tumors characterized by the excessive production of catecholamines. This study aims to describe the clinical characteristics of PPGL cases in Argentina over recent decades. A multicenter retrospective cross-sectional analysis was carried out using a database comprising both pediatric and adult patients with confirmed PPGL diagnoses based on pathological reports. A cohort of 486 patients with PPGL was recruited. Women represent 58.4% of the patients, with a mean age of 38.3 years old at the time of diagnosis and 15.2% of the patients were under the age of 18. Hypertension, as well as classic signs and symptoms, were present in 80.9% of the patients. The adrenal incidentaloma, as a mode of presentation, increased in the last two decades rising from 3.9% (1953-2000) to 21.8% (2001-2022), p<0.001. Most tumors were located within the adrenal glands, accounting 83.0% of the cases, with bilateral occurrences noted in 20.0%. The median tumor size was 4.8cm. Local recurrence and metastases were observed in 10.9% and 12.2%. Out of 412 patients, 87.0% exhibited urinary excretion elevation of catecholamines and/or their metabolites. Furthermore, 148 patients, representing 30.4% of the study population, displayed a distinct genetic profile indicative of hereditary syndromes. The distribution of hereditary syndromes revealed that MEN2, VHL, and PGL4 constituted the most prevalent syndromes. This population-based study, spanning seven decades, offers valuable insights into the demographic and clinical characteristics of PPGL patients in Argentina.

Tumor metabolism in pheochromocytomas: clinical and therapeutic implications

Pheochromocytomas and paragangliomas (PPGLs) have emerged as one of the most common endocrine tumors. It epitomizes fascinating crossroads of genetic, metabolic, and endocrine oncology, providing a canvas to explore the molecular intricacies of tumor biology. Predominantly rooted in the aberration of metabolic pathways, particularly the Krebs cycle and related enzymatic functionalities, PPGLs manifest an intriguing metabolic profile, highlighting elevated levels of oncometabolites like succinate and fumarate, and furthering cellular malignancy and genomic instability. This comprehensive review aims to delineate the multifaceted aspects of tumor metabolism in PPGLs, encapsulating genetic factors, oncometabolites, and potential therapeutic avenues, thereby providing a cohesive understanding of metabolic disturbances and their ramifications in tumorigenesis and disease progression. Initial investigations into PPGLs metabolomics unveiled a stark correlation between specific genetic mutations, notably in the succinate dehydrogenase complex (SDHx) genes, and the accumulation of oncometabolites, establishing a pivotal role in epigenetic alterations and hypoxia-inducible pathways. By scrutinizing voluminous metabolic studies and exploiting technologies, novel insights into the metabolic and genetic aspects of PPGLs are perpetually being gathered elucidating complex interactions and molecular machinations. Additionally, the exploration of therapeutic strategies targeting metabolic abnormalities has burgeoned harboring potential for innovative and efficacious treatment modalities. This review encapsulates the profound metabolic complexities of PPGLs, aiming to foster an enriched understanding and pave the way for future investigations and therapeutic innovations in managing these metabolically unique tumors.

Comprehensive Investigation of Angiogenesis, PASS Score and Immunohistochemical Factors in Risk Assessment of Malignancy for Paraganglioma and Pheochromocytoma

A challenging task in routine practice is finding the distinction between benign and malignant paragangliomas and pheochromocytomas. The aim of this study is to conduct a comparative analysis of angiogenesis by assessing intratumoral microvascular density (MVD) with immunohistochemical (IHC) markers (CD31, CD34, CD105, ERG), and S100 immunoreactivity, Ki67 proliferative index, succinate dehydrogenase B (SDHB) expressiveness, tumor size with one the most utilized score Pheochromocytoma of Adrenal Gland Scales Score (PASS), using tissue microarray (TMA) with 115 tumor samples, 61 benign (PASS < 4) and 54 potentially malignant (PASS ≥ 4). We found no notable difference between intratumoral MVD and potentially malignant behavior. The group of potentially malignant tumors is significantly larger in size, has lower intratumoral MVD, and a decreased number of S100 labeled sustentacular cells. Both groups have low proliferative activity (mean Ki67 is 1.02 and 1.22, respectively). Most tumors maintain SDHB expression, only 6 cases (5.2%) showed a loss of expression (4 of them in PASS < 4 group and 2 in PASS ≥ 4). PASS score is easily available for assessment and complemented with markers of biological behavior to complete the risk stratification algorithm. Size is directly related to PASS score and malignancy. Intratumoral MVD is extensively developed but it is not crucial in evaluating the malignant potential.

Cauda equina neuroendocrine tumor: a report of three cases and review of the literature with focus on differential diagnosis and postoperative management

INTRODUCTION

Cauda equina neuroendocrine tumors (CENETs), previously described as cauda equina paragangliomas (PGLs) are rare and well-vascularized benign entities which can be often misdiagnosed with other intradural tumors more common in this anatomical site, such as ependymomas and neurinomas. We describe three cases of CENETs observed at our institution with particular focus on differential diagnosis and postoperative management. Since the lack of guidelines, we performed a literature review to identify factors that can predict recurrence and influence postoperative decision making.

CASE REPORT AND LITERATURE REVIEW

We report on three patients, two of them presenting with a clinical history of lower back pain and sciatica. In all cases magnetic resonance imaging (MRI) of the lumbosacral spine with and without Gd-DTPA revealed an intradural lesion with strong contrast enhancement, first described as atypical ependymoma or schwannoma. A complete tumor resection was achieved in all cases, the histopathological diagnosis classified the tumors as CENETs. In our literature review, a total of 688 articles were screened and 162 patients were included. Patients demographic data, clinical symptoms, resection and recurrence were recorded.

DISCUSSION

Differential diagnosis between CENETs and other more common tumors affecting cauda equina region, such as ependymomas or schwannomas (neurinomas), is still very challenging. Due to the lack of specific clinical or radiological characteristics, a correct preoperative diagnosis is almost impossible. With this paper we want to point out that CENETs must be considered in the differential diagnosis, most of all in case of entities with atypical radiological features. According to the literature, tumor recurrence after gross total resection is unlikely, while a long-term follow-up is recommended in case of subtotal resection or local aggressive behavior.

Intraoperative radiofrequency ablation for unresectable abdominal paraganglioma: a case report

For pheochromocytoma and paraganglioma (PPGL), the efficacy of percutaneous ablative therapies in achieving control of metastatic tumors measuring <3 cm had been demonstrated in only few reports, and intraoperative radiofrequency ablation (RFA) of locally invasive primary PPGLs has not been reported. We presented the case of a 31-year-old man who had a 9-cm functioning unresectable PPGL. He was treated with 13 cycles of cytotoxic chemotherapy without objective tumor response, according to the Response Evaluation Criteria in Solid Tumors (RECIST). Subsequently, magnetic resonance imaging revealed a 9.0 × 8.6 × 6.0-cm retroperitoneal mass that extended to the inferior portion of the inferior vena cava, the inferior mesenteric artery, and the infrarenal aorta. Biochemical evaluation demonstrated high level of plasma normetanephrine (20.2 nmol/L, normal range <0.9 nmol/L). Genetic investigation showed the germline pathogenic variant c.1591delC (p. Ser198Alafs*22) in the SDHB gene. I131-metaiodobenzylguanidine scintigraphy was negative and Ga68-dotatate PET-CT scan showed high tumor uptake without distant metastases. On open laparotomy, tumor debulking was not possible. Therefore, intraoperative RFA was performed by a highly experienced team of interventional radiologists. At 12 months after the RFA, the tumor volume decreased from 208 to 45 mL (78%), plasma normetanephrine decreased from 20.2 to 2.6 nmol/L (87%), and the doxazosin dose was reduced from 16 to 8 mg/day. To our best knowledge, this was the first report on intraoperative RFA that markedly reduced the size of a large primary unresectable PPGL, along with clinical and biochemical responses.

Diagnosis and management of urinary bladder paragangliomas: A Sino-American-European retrospective observational study

OBJECTIVE

Paragangliomas of the urinary bladder (UBPGLs) are rare neuroendocrine tumours and pose a diagnostic and surgical challenge. It remains unclear what factors contribute to a timely presurgical diagnosis. The purpose of this study is to identify factors contributing to missing the diagnosis of UBPGLs before surgery.

DESIGN, PATIENTS AND MEASUREMENTS

A total of 73 patients from 11 centres in China, and 51 patients from 6 centres in Europe and 1 center in the United States were included. Clinical, surgical and genetic data were collected and compared in patients diagnosed before versus after surgery. Logistic regression analysis was used to identify clinical factors associated with initiation of presurgical biochemical testing.

RESULTS

Among all patients, only 47.6% were diagnosed before surgery. These patients were younger (34.0 vs. 54.0 years, p < .001), had larger tumours (2.9 vs. 1.8 cm, p < .001), and more had a SDHB pathogenic variant (54.7% vs. 11.9%, p < .001) than those diagnosed after surgery. Patients with presurgical diagnosis presented with more micturition spells (39.7% vs. 15.9%, p = .003), hypertension (50.0% vs. 31.7%, p = .041) and catecholamine-related symptoms (37.9% vs. 17.5%, p = .012). Multivariable logistic analysis revealed that presence of younger age (<35 years, odds ratio [OR] = 6.47, p = .013), micturition spells (OR = 6.79, p = .007), hypertension (OR = 3.98, p = .011), and sweating (OR = 41.72, p = .013) increased the probability of initiating presurgical biochemical testing.

CONCLUSIONS

Most patients with UBPGL are diagnosed after surgery. Young age, hypertension, micturition spells and sweating are clues in assisting to initiate early biochemical testing and thus may establish a timely presurgical diagnosis.

Long-Term Surgical Outcome of Class A and B Tympanomastoid Paragangliomas

OBJECTIVE

To analyze the long-term facial function as well as overall postoperative condition in surgically treated tympanomastoid PGL patients.

STUDY DESIGN

Retrospective study.

METHOD

The medical records of patients with surgically managed class A and B tympanomastoid PGLs between 1983 and 2023 were thoroughly evaluated.

RESULT

Our center has treated a total of 213 cases of tympanomastoid PGL surgically. The mean age of patients was 54, and the male-to-female ratio was 1:6. The most common symptoms at presentation were hearing loss (80%), pulsatile tinnitus (77%), and vertigo (15%). According to the modified Fisch classification, 45% of the cases were classified as class A (A1 and A2), while 55% were classified as class B (B1, B2, and B3). All class A and most class B1 and B2 tumors were removed either with transcanal or retroauricular-transcanal approaches. However, more advanced class B3 lesions were removed with subtotal petrosectomy (SP) along with middle ear obliteration. Facial nerve outcome was excellent in all class A and B cases, while chances of postoperative paresis slightly increased with the size and extent of the tumor (p < 0.05). The hearing outcome is excellent for class A1, A2, B1, and B2 tumors, whereas more advanced class B3 cases have a loss of air conduction (AC) and increased bone conduction (BC) threshold (p < 0.05). Complete surgical removal was achieved in 97% of our cases. The most common late complication was permanent TM perforation (7%), and the recurrence rate was 3%.

CONCLUSIONS

Tympanomastoid PGL represents the most common neoplasm of the middle ear space. The most frequent presenting symptoms include pulsatile tinnitus and hearing loss, whereas the presence of retrotympanic mass was evident in all cases at the time of initial otoscopic evaluation. Proper documentation of facial function and audiometric evaluation are crucial elements of preoperative workup. The most preferred preoperative radiologic examination is high-resolution computer tomography (HRCT), whereas magnetic resonance imaging (MRI) with or without gadolinium enhancement is reserved for cases with a dilemma of carotid artery or jugular bulb involvement. The main goal of tympanomastoid PGL treatment is complete disease removal with preservation of hearing and facial functions. Surgical treatment remains the preferred treatment modality with the benefits of complete disease removal, lower rate of recurrence and complication, and acceptable postoperative hearing level. Here, we present our 40 years of experience, which, to the very best of our knowledge, is the largest series of tympanomastoid PGL in the English literature.

Automated sample preparation for electrospray ionization mass spectrometry based on CLOCK-controlled autonomous centrifugal microfluidics

We report a centrifugal microfluidic device that automatically performs sample preparation under steady-state rotation for clinical applications using mass spectrometry. The autonomous microfluidic device was designed for the control of liquid operation on centrifugal hydrokinetics (CLOCK) paradigm. The reported device was highly stable, with less than 7% variation with respect to the time of each unit operation (sample extraction, mixing, and supernatant extraction) in the preparation process. An agitation mechanism with bubbling was used to mix the sample and organic solvent in this device. We confirmed that the device effectively removed the protein aggregates from the sample, and the performance was comparable to those of conventional manual sample preparation procedures that use high-speed centrifugation. In addition, probe electrospray ionization mass spectrometry (PESI-MS) was performed to compare the device-treated and manually treated samples. The obtained PESI-MS spectra were analyzed by partial least squares discriminant analysis, and the preparation capability of the device was found to be equivalent to that of the conventional method.

Exploration of factors affecting hemodynamic stability following pheochromocytoma resection - cohort study

Purpose

Surgery is the only way to cure pheochromocytoma; however, postoperative hemodynamic instability is one of the main causes of serious complications and even death. This study's findings provide some guidance for improved clinical management.

Patients and methods

This study was to investigate the factors leading to postoperative hemodynamic instability in the postoperative pathology indicated pheochromocytoma from May 2016 to May 2022. They were divided into two groups according to whether vasoactive drugs were used for a median number of days or more postoperatively. The factors affecting the postoperative hemodynamics in the perioperative period (preoperative, intraoperative, and postoperative) were then evaluated.

Results

The median number of days requiring vasoactive drug support postoperatively was three in 234 patients, while 118 (50.4%) patients required vasoactive drug support for three days or more postoperatively. The results of the multivariate analysis indicated more preoperative colloid use (odds ratio [OR]=1.834, confidence interval [CI]:1.265-2.659, P=0.001), intraoperative use of vasoactive drug (OR=4.174, CI:1.882-9.258, P<0.001), and more postoperative crystalloid solution input per unit of body weight per day (ml/kg/d) (OR=1.087, CI:1.062-1.112, P<0.001) were risk factors for predicting postoperative hemodynamic instability. The optimal cutoff point of postoperative crystalloid use were 42.37 ml/kg/d.

Conclusion

Hemodynamic instability is a key issue for consideration in the perioperative period of pheochromocytoma. The amount of preoperative colloid use, the need for intraoperative vasoactive drugs, and postoperative crystalloid solution are risk factors for predicting postoperative hemodynamic instability (registration number: ChiCT2300071166).

3-[18F]Fluoro-para-hydroxyphenethylguanidine (3-[18F]pHPG) PET-A Novel Imaging Modality for Paraganglioma

Context

Functional positron emission tomography (PET) imaging for the characterization of pheochromocytoma and paraganglioma (PCC/PGL) and for detection of metastases in malignant disease, offers valuable clinical insights that can significantly guide patient treatment.

Objective

This work aimed to evaluate a novel PET radiotracer, 3-[18F]fluoro-para-hydroxyphenethylguanidine (3-[18F]pHPG), a norepinephrine analogue, for its ability to localize PCC/PGL.

Methods

3-[18F]pHPG PET/CT whole-body scans were performed on 16 patients (8 male:8 female; mean age 47.6 ± 17.6 years; range, 19-74 years) with pathologically confirmed or clinically diagnosed PCC/PGL. After intravenous administration of 304 to 475 MBq (8.2-12.8 mCi) of 3-[18F]pHPG, whole-body PET scans were performed at 90 minutes in all patients. 3-[18F]pHPG PET was interpreted for abnormal findings consistent with primary tumor or metastasis, and biodistribution in normal organs recorded. Standardized uptake value (SUV) measurements were obtained for target lesions and physiological organ distributions.

Results

3-[18F]pHPG PET showed high radiotracer uptake and trapping in primary tumors, and metastatic tumor lesions that included bone, lymph nodes, and other solid organ sites. Physiological biodistribution was universally present in salivary glands (parotid, submandibular, sublingual), thyroid, heart, liver, adrenals, kidneys, and bladder. Comparison [68Ga]DOTATATE PET/CT was available in 10 patients and in all cases showed concordant distribution. Comparison [123I]meta-iodobenzylguanidine [123I]mIBG planar scintigraphy and SPECT/CT scans were available for 4 patients, with 3-[18F]pHPG showing a greater number of metastatic lesions.

Conclusion

We found the kinetic profile of 3-[18F]pHPG PET affords high activity retention within benign and metastatic PCC/PGL. Therefore, 3-[18F]pHPG PET imaging provides a novel modality for functional imaging and staging of malignant paraganglioma with advantages of high lesion affinity, whole-body coregistered computed tomography, and rapid same-day imaging.

Management of Abdominal Paraganglioma: A Single Center's Experience

Background and Objectives: Paragangliomas (PGLs) are rare neuroendocrine extra-adrenal tumors that could be secreting mass. The symptoms are the typical triad of paroxysmal headache, hypertension and sweating, but could also be accompanied by symptoms involving multiple organs. Surgery is the gold standard treatment for both PGLs and pheochromocytomas (PHEOs). Material and Methods: We used a computerized endocrine surgery registry to record the demographic and clinical data of 153 patients who underwent surgery for PPGL between 2010 and 2023 at our hospital. Results: Thirteen patients (8.43%) with paragangliomas underwent surgery at our institute. Five patients presented symptomatic syndrome. Preoperative investigations included enhanced abdominal CT (nine patients) and enhanced MRI (seven patients). In cases of suspicious mass, we performed 131I-MIBG scans (two patients) or 68GA-DOTATOC PET-CT scans (11 patients). Laparoscopic approach was used in four cases (30.7%) and abdominal laparotomy in the other nine (69.3%). Biochemical tests were performed on all patients. Conclusions: In this retrospective study, we discuss the multidisciplinary management in our institute of this rare disease, from its challenging diagnosis to the surgical strategy for PGLs. Laparoscopic surgery is the gold standard, but a tailored approach should be adopted for each patient.

Pitfalls in the Diagnostic Evaluation of Pheochromocytomas

Pheochromocytomas and paragangliomas (PPGLs), rare neuroendocrine tumors arising from chromaffin cells, present a significant diagnostic challenge due to their clinical rarity and polymorphic symptomatology. The clinical cases demonstrate the importance of an integrated approach that combines clinical assessment, biochemical testing, and imaging to distinguish PPGLs from mimicking conditions, such as obstructive sleep apnea and interfering medication effects, which can lead to false-positive biochemical results. Although a rare condition, false-negative metanephrine levels can occur in pheochromocytomas, but imaging findings can give some clues and increase suspicion for a pheochromocytoma diagnosis. This expert endocrine consult underscores the critical role of evaluating preanalytical conditions and pretest probability in the biochemical diagnosis of PPGLs. Moreover, a careful differentiation of PPGLs from similar conditions and careful selection and interpretation of diagnostic tests, with focus on understanding and reducing false positives to enhance diagnostic accuracy and patient outcomes, is crucial.

Hormonally Silent Multifocal Pheochromocytoma in the Setting of a Well-Differentiated Neuroendocrine Tumor of the Appendix: A Case Report

Pheochromocytomas (PCCs) and paragangliomas (PGLs) represent tumors arising from chromaffin cells of the adrenal medulla and extra-adrenal sympathetic paraganglia, respectively. PCCs commonly produce one or more catecholamines (epinephrine, norepinephrine, and dopamine), but rarely are they biochemically silent. PGLs on the other hand, generally do not produce catecholamines. They have the highest heritability of all adrenal tumors and are known to be associated with genetic mutations. Patients with hereditary tumors typically present at a younger age and with multifocal disease when compared to sporadic disease. Specific genetic mutations have been well established with hereditary syndromes involving PCC/PGLs. Further research has aimed to identify other mutations and delineate specific phenotypes associated with these mutations. A 34-year-old woman presented for evaluation following a laparoscopic appendectomy that identified a 4-cm well-differentiated neuroendocrine tumor on final pathology. Further work-up included a repeat CT scan followed by a Dotatate PET CT scan which revealed a large (7.3 x 5.8 cm) periaortic mass related to the left adrenal gland. Functional adrenal work-up was negative and her Chromogranin A level was 679 ng/mL. She did report intermittent chest tightness and palpitations but was otherwise asymptomatic. The patient subsequently underwent an exploratory laparotomy with left adrenalectomy and adjacent tumor resection as well as completion of right hemicolectomy with ileocolonic anastomosis. Surgical pathology revealed two distinct masses consistent with multifocal PCC. No residual tumor was found in the colectomy specimen and 24 lymph nodes were negative. She had an uneventful recovery and genetic testing showed a variant of uncertain significance for the POLE and VHL genes. She has received genetic counseling and will be enrolled in an appropriate surveillance protocol.

Ambulatory blood pressure monitoring in pheochromocytoma - paraganglioma: A single center experience

CONTEXT/AIMS

Pheochromocytoma and paraganglioma (PPGL) are rare tumors, and data on ambulatory blood pressure monitoring (ABPM) in these patients and the effect of blocking on ABPM parameters is limited. We aimed to describe ABPM parameters in a cohort of PPGL at our center in western India.

METHODS

Retrospective study of patients with PPGL whose ABPM data was available. Demographic details, secretory status, and ABPM data were retrieved. Coefficient of variability (CV) was calculated as standard deviation/mean in percentage.

RESULTS

In the 39 included patients, mean age at presentation was 39.3 ± 14.2 yr; 20 (51.3%) were males, 25 (64.1%) hypertensive, and mean tumor diameter was 5.3 cm. In 18 patients whose baseline ABPM was done without medications, those with nocturnal blood pressure dipping (6/18, 33%) had higher serum metanephrines (median 313.2 vs. 34.7 pg/ml, P = 0.028). Despite normal office blood pressure (BP), 8.9% of systolic BP readings were >140 mmHg, and 1.2% were >160 mmHg. Among 29 patients with both pre and post-block ABPM, mean BP (systolic 121.6 vs. 132.5 mmHg, P = 0.014; diastolic 68.9 vs. 76.4 mmHg, P = 0.005) and percentage of BP readings above 140 mmHg (median 9.4% vs. 24.4%, P = 0.016) were significantly lowered after the preoperative blockade in hypertensive ( n = 19) patients, whereas CV was similar. The post-blockade ABPM characteristics were similar in patients blocked with amlodipine or prazosin.

CONCLUSION

ABPM provides additional information about BP characteristics in PPGL. The preoperative blocking decreases the magnitude of BP excursions but does not affect BP variability.

177 Lu-DOTATATE in the Treatment of Recurrent Pheochromocytoma With Multiple Metastases

ABSTRACT

The treatment of metastatic pheochromocytoma is challenging. We report a case of a woman with recurrent pheochromocytoma with multiple metastases who achieved excellent response after 4 cycles of 177 Lu-DOTATATE therapy. She did not experience any observable adverse effects. Her disease was still stable 6 months after the fourth cycle of treatment.