Genetic testing for pheochromocytoma-associated syndromes

Suprasellar paraganglioma in a clinical setting of von Hippel-Lindau syndrome

A man in his 20s presented to the neurosurgery department 2 years ago with headache and blurred vision. He was diagnosed to have a suprasellar mass on neuroimaging. Best-corrected visual acuity in the right eye was 6/36 and that in the left eye was 6/60. Automated visual fields showed a temporal hemianopia in the right eye and an advanced field defect in the left eye. His hormonal profile was normal, and he underwent partial excision of suprasellar tumour, which was a histopathologically proven paraganglioma (PGL). Subsequently, the patient underwent radiotherapy and his vision and visual fields showed improvement. Follow-up examination 3 years later showed a left retinal capillary hemangioblastoma (RCH), which was treated with green laser photocoagulation, resulting in complete sclerosis. This case is unique because of the extremely rare coexistence of a sellar PGL and RCH, which to our knowledge has not been reported so far.

Adrenal Incidentaloma Needs thorough Biochemical Evaluation - An Institutional Experience

CONTEXT

Adrenal incidentalomas (AIs) are seen in around 2% of apparently healthy individuals. These require careful evaluation for the hormone excess state and the presence of malignancy prior to intervention.

AIMS

To study the clinical, biochemical, and imaging characteristics of the patients with AI and correlate the diagnosis with the histopathology findings in patients undergoing surgery.

SETTINGS AND DESIGN

Retrospective observational study.

METHODS AND MATERIAL

Patients with adrenal incidentaloma presenting between January 2017 and January 2021 were evaluated as per guidelines provided by the European Society of Endocrinology and the European Network for the Study of Adrenal Tumors. Patients were given final diagnosis on the basis of imaging impression, hormonal activity, and biopsy results (when applicable).

RESULTS

Forty-eight patients were evaluated, with 25 being male, the mean age being 40.9 years (8-71), and the mean size of the mass being 6.21 (1.4-13.7) cm. Thirty-five (72.9%) of them underwent surgical excision. The most common diagnosis was myelolipoma (16), followed by pheochromocytoma (10) and adenoma (9). Nineteen patients were found to have hormone-secreting masses. Two patients with pheochromocytoma were normotensive. There was discordance between imaging diagnosis and hormonal status in two patients, with final diagnosis of pheochromocytoma. One patient with extramedullary erythropoiesis of the adrenal gland was subsequently diagnosed with sickle cell anemia and adrenal insufficiency.

CONCLUSIONS

The study highlights the rare possibility of discrepancy between non-contrast CT diagnosis and functional status of AI. There is also a rare possibility of extramedullary erythropoiesis presenting as AI with adrenal insufficiency. Specific evaluation for such rare possibilities should be considered in AI cases as per clinical scenario.

Adrenal Incidentaloma

An adrenal incidentaloma is now established as a common endocrine diagnosis that requires a multidisciplinary approach for effective management. The majority of patients can be reassured and discharged, but a personalized approach based upon image analysis, endocrine workup, and clinical symptoms and signs are required in every case. Adrenocortical carcinoma remains a real concern but is restricted to <2% of all cases. Functional adrenal incidentaloma lesions are commoner (but still probably <10% of total) and the greatest challenge remains the diagnosis and optimum management of autonomous cortisol secretion. Modern-day surgery has improved outcomes and novel radiological and urinary biomarkers will improve early detection and patient stratification in future years to come.

Educational Case: Pheochromocytoma

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, see http://journals.sagepub.com/doi/10.1177/2374289517715040.

Pheochromocytoma after Cesarean Section

Pheochromocytoma is a catecholamine-producing tumor. There are a very few reported cases of clinical pheochromocytoma. Here, we report a 27-year-old woman para 1 live 1 with chief complaint of headache, confusion, nausea, and vomiting 2 days after cesarean section. She was anxious and had palpitation. On physical examination, fever, tachycardia, tachypnea, high blood pressure, and right thyroid nodule were found. She was managed as pregnancy-induced hypertension at first. In laboratory data, epinephrine, norepinephrine, metanephrine, normetanephrine, and vanillylmandelic acid were increased in 24 h urine collection. An adrenal mass was detected in abdominal computed tomography. Regarding clinical and paraclinical findings, pheochromocytoma was diagnosed. The patient received medical treatment, but it was not effective; hence, she underwent adrenalectomy.

Succinate-to-fumarate ratio as a new metabolic marker to detect the presence of SDHB/D-related paraganglioma: initial experimental and ex vivo findings

Pheochromocytomas (PHEOs) and paragangliomas (PGLs; extra-adrenal tumors) are rare neuroendocrine chromaffin cell tumors with a hereditary background in about 30%-35%. Those caused by succinate dehydrogenase subunit B (SDHB) germline mutations are associated with a high metastatic potential and ultimately higher patient mortality. Succinate dehydrogenase converts succinate to fumarate, uniquely linking the Krebs cycle and oxidative phosphorylation. SDH mutations result in the accumulation of succinate associated with various metabolic disturbances and the shift to aerobic glycolysis in tumor tissue. In the present study, we measured succinate and fumarate levels in mouse pheochromocytoma (MPC) and mouse tumor tissue (MTT) cells and in 10 apparently sporadic, 10 SDHB-, 5 SDHD-, and 2 neurofibromatosis 1-related PHEOs/PGLs and plasma samples using mass spectrometry. We found that the succinate-to-fumarate ratio was significantly higher in the SDHB- and SDHD-related PGLs than in apparently sporadic and neurofibromatosis 1-related PHEOs/PGLs (P = .0376). To further support our data, we silenced SDHB expression in MPC and MTT cells and evaluated the succinate and fumarate levels. Compared with control samples, SDHB-silenced MTT cells also showed an increase in the succinate-to-fumarate ratio (MTT cells: 2.45 vs 7.53), similar to the findings in SDHB-related PGLs. The present findings for the first time demonstrate a significantly increased succinate-to-fumarate ratio in SDHB/D-related PGLs and thus suggest this ratio may be used as a new metabolic marker for the detection of SDHB/D-related PHEOs/PGLs.

Pancreatic lesions in von Hippel-Lindau disease? A systematic review and meta-synthesis of the literature

BACKGROUND

von Hippel-Lindau (vHL) disease is a rare condition that leads to characteristic lesions within many different body systems. Pancreatic manifestations of vHL cover a wide spectrum of pathologies, and thus, accurate characterization and management is critical.

METHODS

A comprehensive and systematic text word and MeSH search of the medical literature was performed to identify studies where information regarding the prevalence, clinical characteristics, and management recommendations could be extracted.

RESULTS

Eleven studies were identified but 2 studies utilized the same data set. Of the 10 remaining studies, a total of 1,442 patients with vHL were available for analysis. Four hundred and twenty patients were examined for any type of pancreatic lesion, 362 for simple cysts or serous cystadenomas (SCAs), and 1,442 for neuroendocrine tumors (NETs). Of the 420 assessed for any pancreatic manifestation of vHL, 252 (60%) had a pancreatic lesion identified. Simple cysts that present as the sole manifestation of pancreatic disease were common and found in 169 of 362 (47%) patients. These are usually asymptomatic and do not normally require intervention. SCAs were reported in 39 of 362 (11%) patients and followed a similar benign course; resection is acceptable in symptomatic patients. NETs were identified in 211 of 1,442 (15%) patients, and 27 of 1,442 (2%) lesions behaved malignantly. Management of NETs depends on size, doubling time, and underlying genetics. Renal cell carcinoma is a characteristic in vHL, but there were no cases of pancreatic metastases identified from the included studies. Adenocarcinomas of the pancreas are not pathogenically linked to vHL.

CONCLUSIONS

This review highlights the wide spectrum and high prevalence of pancreatic lesions in vHL. Simple cysts and SCAs are benign, but NETs require careful observation due to their malignant potential.

Paragangliomas: etiology, presentation, and management

Paragangliomas are catecholamine-secreting tumors arising from the chromaffin cells of the sympathetic ganglia, and are known as extra-adrenal pheochromocytomas. These tumors commonly present with episodic hypertension, tachycardia, headache, and diaphoresis, and can be either benign or malignant. Diagnosis is made by serum and urine analysis for catecholamines and metanephrines, and confirmed with imaging studies including computed tomography scanning, magnetic resonance imaging, or 123-I metaiodobenzylguanidine imaging. Although the majority of paragangliomas are sporadic, a growing percentage of cases are found to be part of a familial genetic syndrome. Genetic testing should be offered to patients diagnosed with paraganglioma, particularly in patients who are young, have multiple tumors, or have a family history of malignancy. Management of paraganglioma is predicated on surgical resection, and careful perioperative management with alpha- and beta-adrenergic blockade is imperative for optimal outcomes. The majority of these tumors are benign, but for patients with malignant disease, chemotherapy, and radiation therapy may provide modest benefit. Long-term follow-up is essential, as paragangliomas can recur many years after initial diagnosis. Ongoing research into the genetic underpinnings of this tumor may allow for more targeted molecular therapies in the future.

[Pheochromocytoma - still a challenge]

Pheochromocytomas are rare, mostly benign catecholamine-producing tumors arising from the chromaffin cells of the adrenal medulla or in the paraganglia. Clinical presentation is highly variable but typically with hypertension, severe headaches, palpitations and sweating. Biochemical testing by 24 h urinary fractioned metanephrines or catecholamines and plasma free metanephrines as the most sensitive screening approach, confirms the catecholamine excess. Computed tomography scan and magnetic resonance imaging of the adrenal glands and abdomen as well as functional imaging with (123)Iod-MIBG scintigraphy and (18)F-dopa positron emission tomography are used for tumor localization. Because approximately a quarter of tumors develop secondary to germ-line mutations, screening for genetic alterations is important. The therapy of choice is the endoscopic adrenal sparing surgery following preoperative alpha-blockade. Regular follow-up remains essential due to possible recurrence and malignancy.

Adrenal causes of hypertension: pheochromocytoma and primary aldosteronism

The clinical presentations of the patient with pheochromocytoma -- a rare endocrine neoplasm -- include adrenal incidentaloma, hypertensive paroxysms, sustained apparent polygenic hypertension, hypertension in pregnancy, and hypertensive crisis induced by anesthesia. Although when undiagnosed a pheochromocytoma can be lethal, it can usually be cured with surgery. Biochemical documentation with measurements of fractionated metanephrines and catecholamines should precede imaging studies. Abdomen and pelvis computed imaging is usually the first imaging test. Careful preoperative pharmacologic preparation is important for a successful surgical outcome. Adrenal pheochromocytomas can usually be removed laparoscopically, whereas, catecholamine-secreting paragangliomas typically require an open approach. All first degree relatives of pheochromocytoma patients should have biochemical testing. In addition, molecular genetic testing for germline mutations should be considered in most patients with adrenal pheochromocytoma and in all patients with paraganglioma. Primary aldosteronism is a relatively common form of secondary hypertension -- affecting 5 to 10% of all patients with hypertension. A plasma aldosterone concentration (PAC) to plasma renin activity (PRA) ratio should be obtained in patients with hypertension and hypokalemia, resistant hypertension, adrenal incidentaloma and hypertension, onset of hypertension at a young age (e.g., < 20 years of age), severe hypertension (e.g., > or =160 mm Hg systolic or > or =100 mm Hg diastolic), or whenever the clinician is considering other forms of secondary hypertension. The PAC/PRA ratio is a case finding test and a positive result should be confirmed with aldosterone suppression testing with either oral or intravenous sodium loading. The treatment goals for patients with primary aldosteronism are to prevent the morbidity and mortality associated with hypertension, hypokalemia, and cardiovascular damage. Both the subtype of primary aldosteronism and patient preference should dictate the treatment approach.

Pheochromocytoma: presentation, diagnosis and treatment

Pheochromocytomas are rare, mostly benign catecholamine-producing tumors of chromaffin cells of the adrenal medulla or of a paraganglion. Typical clinical manifestations are sustained or paroxysmal hypertension, severe headaches, palpitations and sweating resulting from hormone excess. However, their presentation is highly variable and can mimic many other diseases. If remaining unrecognized or untreated, they can be a life-threatening condition. Therefore, the most important message of this review is to think of them. The diagnosis of pheochromocytomas depends mainly upon the demonstration of catecholamine excess by 24-h urinary catecholamines and metanephrines or plasma metanephrines. They are localized by a computed tomography scan and magnetic resonance imaging of the adrenal glands and abdomen; complementary 123I-metaiodobenzylguanidine scintigraphy and 18F-dihydroxyphenylalanine-positron emission tomography are available. Because approximately one out of four pheochromocytomas turn out to be hereditary entities, screening for genetic alterations is important. Laparoscopic and adrenal sparing surgical intervention following preoperative alpha-blockade is the treatment of choice and usually curative. In malignant pheochromocytomas, radiotherapy and chemotherapy are palliative treatment options. This review provides an update on identification and management of pheochromocytomas, emphasizing current developments in diagnosis, including genetic testing, pathophysiology and treatment of pheochromocytomas.

Stephen L. Gans Distinguished Overseas Lecture. The neural crest in pediatric surgery

AIM

This review highlights the relevance of the neural crest (NC) as a developmental control mechanism involved in several pediatric surgical conditions and the investigative interest of following some of its known signaling pathways.

METHODS

The participation of the NC in facial clefts, ear defects, branchial fistulae and cysts, heart outflow tract and aortic arch anomalies, pigmentary disorders, abnormal enteric innervation, neural tumors, hemangiomas, and vascular anomalies is briefly reviewed. Then, the literature on clinical and experimental esophageal atresia-tracheoesophageal fistula (EA-TEF) and congenital diaphragmatic hernia (CDH) is reviewed for the presence of associated NC defects. Finally, some of the molecular signaling pathways involved in both conditions (sonic hedgehog, Hox genes, and retinoids) are summarized.

RESULTS

The association of facial, cardiovascular, thymic, parathyroid, and C-cell defects together with anomalies of extrinsic and intrinsic esophageal innervation in babies and/or animals with both EA-TEF and CDH strongly supports the hypothesis that NC is involved in the pathogenesis of these malformative clusters. On the other hand, both EA-TEF and CDH are observed in mice mutant for genes involved in the previously mentioned signaling pathways.

CONCLUSIONS

The investigation of NC-related molecular pathogenic pathways involved in malformative associations like EA-TEF and CDH that are induced by chromosomal anomalies, chemical teratogens, and engineered mutations is a promising way of clarifying why and how some pediatric surgical conditions occur. Pediatric surgeons should be actively involved in these investigations.

Pancreatic involvement in von Hippel-Lindau disease: report of two cases and review of the literature

BACKGROUND

Von Hippel-Lindau (VHL) disease is an autosomal dominant multicancer syndrome caused by the germline mutation of a tumor suppressor gene. Affected individuals develop benign and malignant tumors of the central nervous system, kidneys, adrenal glands, pancreas, and reproductive system. Although VHL disease is mainly diagnosed after the detection of central nervous system tumors, they may not always be the first presentation.

CASE REPORT

We report the case of a patient presenting with pancreatic cysts for whom the final genetic diagnosis of VHL disease was formulated. During management, the use of endoscopic ultrasonography (EUS) proved to be valid in the characterization of the pancreatic lesions. Family screening also revealed the genetic mutation in the patient's son and imaging investigations showed the presence of multiple tumors. The diagnosis allowed us to plan appropriate follow-up for both, thus improving their life expectancy.

CONCLUSIONS

Gastroenterologists should be aware of the frequent pancreatic involvement in VHL disease and EUS can be useful in this setting.