Pheochromocytoma and paraganglioma: diagnosis, genetics, management, and treatment

Successful Treatment of Coexisting Paraganglioma of the Retroperitoneum and Urinary Bladder by Intermediate-Dose 131I-MIBG Therapy: A Case Report

Paragangliomas (PGLs) are rare neuroendocrine neoplasms of the autonomic nervous system dispersed from the skull base to the pelvic floor. We reported an extremely rare case with coexisting PGL of the retroperitoneum and urinary bladder. The patient complained of episodes of severe headache and palpitation during micturition, with a 1-year history of uncontrolled hypertension. The (131)I-metaiodobenzylguanidine ((131)I-MIBG) scintigraphy revealed high uptake in both of the retroperitoneum and urinary bladder mass accompanied with increasing 24 hour urinary norepinephrine and epinephrine. The patient received 6 doses of high-specific activity (131)I-MIBG from October 2009 to April 2015, each treatment dose was 400 mCi. The patient got symptomatic, hormonal, and radiographic tumor complete response without life-threatening adverse events.Intermediate-dose (131)I-MIBG therapy may be an alternative choice for patients with multicentric PGLs with positive MIBG scintigraphy.

18F-FLT PET/CT in the Evaluation of Pheochromocytomas and Paragangliomas: A Pilot Study

(18)F-FDG PET/CT has been proven to be a highly sensitive method for pheochromocytomas/paragangliomas (PHEOs/PGLs) associated with succinate dehydrogenase (SDH) mutations. This finding has been attributed to altered tumor cell metabolism resulting from these mutations and does not provide additional prognostic information to genotype. Therefore, identification of new biomarkers for aggressiveness is needed. A high Ki-67 index was proposed to be an additional prognostic factor. This pilot study aimed to evaluate 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) PET/CT, a PET proliferation tracer, as a potential imaging agent in a series of 12 PHEO/PGL patients with different genetic backgrounds, to compare (18)F-FLT uptake with (18)F-FDG PET/CT, and to evaluate classic factors of aggressiveness.

METHODS

Twelve patients (7 metastatic and 5 nonmetastatic) were prospectively evaluated with (18)F-FDG and (18)F-FLT and followed for at least 2 y after the initial imaging work-up. Uptake was assessed at a lesion level, visually and quantitatively by maximum standardized uptake values (SUVmax) for both tracers. (18)F-FLT uptake was compared with risk factors known to be linked with a poor prognosis in PGLs (SDHB-mutated status, lesion size, dopaminergic phenotype) and with (18)F-FDG uptake.

RESULTS

In 12 patients, 77 lesions were assessed. All lesions had low (18)F-FLT uptake (median SUVmax, 2.25; range, 0.7-4.5). There was no apparent superiority of (18)F-FLT uptake in progressive lesions, and most of the lesions showed a mismatch, with high (18)F-FDG uptake (median SUVmax, 10.8; range, 1.1-79.0) contrasting with low (18)F-FLT uptake.

CONCLUSION

This study suggests that PHEOs/PGLs-even those that progress-do not exhibit intense (18)F-FLT uptake. It provides the first in vivo demonstration that proliferation may not be a major determinant of (18)F-FDG uptake in these tumors. These findings provide new insight into the biologic behavior of PGL and suggest that antiproliferative agents may be suboptimal for treatment of these tumors.

Incidental retroperitoneal paraganglioma in patient candidate to radical prostatectomy: Concurrent surgical treatments by robotic approach

We report a case of a 75-year-old male with biopsy-proven prostate cancer and candidate for radical prostatectomy. The patient's medical history includes hypertension and atrial fibrillation in prophylactic treatment; however, he was suffering from recurrent paroxysmal episodes of supraventricular tachycardia. Abdominal magnetic resonance performed for prostate cancer staging detected a non-lymphatic inter-cavo-aortic mass of 42 × 37 × 43 cm. Results of biochemical screening confirmed the clinical diagnosis of symptomatic paraganglioma. The patient was subjected in a single robotic session for concurrent excision of the inter-aortocaval mass and radical prostatectomy with bilateral pelvic lymph-node dissection. During the procedure, there were no anesthesiological or surgical complications. The postoperative course was uneventful and the patient was discharged on postoperative day 5. Six months after surgery, his prostate-specific antigen level was undetectable and the abdominal magnetic resonance imaging was negative for local recurrence or metastasis of paraganglioma. No more episodes of tachycardia were reported or antihypertensive therapy was necessary.

15 YEARS OF PARAGANGLIOMA: Metabolism and pheochromocytoma/paraganglioma

The discovery of SDHD as a pheochromocytoma/paraganglioma susceptibility gene was the prismatic event that led to all of the subsequent work highlighting the key roles played by mitochondria in the pathogenesis of these tumors and other solid cancers. Alterations in the function of tricarboxylic acid cycle enzymes can cause accumulation of intermediate substrates and subsequent changes in cell metabolism, activation of the angiogenic pathway, increased reactive oxygen species production, DNA hypermethylation, and modification of the tumor microenvironment favoring tumor growth and aggressiveness. The elucidation of these tumorigenic mechanisms should lead to novel therapeutic targets for the treatment of the most aggressive forms of pheochromocytoma/paraganglioma.

Bioinformatic Challenges in Clinical Diagnostic Application of Targeted Next Generation Sequencing: Experience from Pheochromocytoma

Background

Recent studies have demonstrated equal quality of targeted next generation sequencing (NGS) compared to Sanger Sequencing. Whereas these novel sequencing processes have a validated robust performance, choice of enrichment method and different available bioinformatic software as reliable analysis tool needs to be further investigated in a diagnostic setting.

Methods

DNA from 21 patients with genetic variants in SDHB, VHL, EPAS1, RET, (n=17) or clinical criteria of NF1 syndrome (n=4) were included. Targeted NGS was performed using Truseq custom amplicon enrichment sequenced on an Illumina MiSEQ instrument. Results were analysed in parallel using three different bioinformatics pipelines; (1) Commercially available MiSEQ Reporter, fully automatized and integrated software, (2) CLC Genomics Workbench, graphical interface based software, also commercially available, and ICP (3) an in-house scripted custom bioinformatic tool.

Results

A tenfold read coverage was achieved in between 95-98% of targeted bases. All workflows had alignment of reads to SDHA and NF1 pseudogenes. Compared to Sanger sequencing, variant calling revealed a sensitivity ranging from 83 to 100% and a specificity of 99.9-100%. Only MiSEQ reporter identified all pathogenic variants in both sequencing runs.

Conclusions

We conclude that targeted next generation sequencing have equal quality compared to Sanger sequencing. Enrichment specificity and the bioinformatic performance need to be carefully assessed in a diagnostic setting. As acceptable accuracy was noted for a fully automated bioinformatic workflow, we suggest that processing of NGS data could be performed without expert bioinformatics skills utilizing already existing commercially available bioinformatics tools.

Multifocal Extra-Adrenal Paraganglioma - Case Report

Paraganglioma is a rare neoplasm originating from extra-adrenal pheochromocytes of the sympathetic and parasympathetic nervous system. It is usually benign and the treatment method of choice is a complete resection of the tumour. The authors present a case of 66-year-old female patient with a multifocal benign retroperitoneal paraganglioma, which was completely removed during surgery.

Magnetic resonance spectroscopy of paragangliomas: new insights into in vivo metabolomics

Paragangliomas (PGLs) can be associated with mutations in genes of the tricarboxylic acid (TCA) cycle. Succinate dehydrogenase (SDHx) mutations are the prime examples of genetically determined TCA cycle defects with accumulation of succinate. Succinate, which acts as an oncometabolite, can be detected by ex vivo metabolomics approaches. The aim of this study was to evaluate the potential role of proton magnetic resonance (MR) spectroscopy ((1)H-MRS) for identifying SDHx-related PGLs in vivo and noninvasively. Eight patients were prospectively evaluated with single voxel (1)H-MRS. MR spectra from eight tumors (four SDHx-related PGLs, two sporadic PGLs, one cervical schwannoma, and one cervical neurofibroma) were acquired and interpreted qualitatively. Compared to other tumors, a succinate resonance peak was detected only in SDHx-related tumor patients. Spectra quality was considered good in three cases, medium in two cases, poor in two cases, and uninterpretable in the latter case. Smaller lesions had lower spectra quality compared to larger lesions. Jugular PGLs also exhibited a poorer spectra quality compared to other locations. (1)H-MRS has always been challenging in terms of its technical requisites. This is even more true for the evaluation of head and neck tumors. However, (1)H-MRS might be added to the classical MR sequences for metabolomic characterization of PGLs. In vivo detection of succinate might guide genetic testing, characterize SDHx variants of unknown significance (in the absence of available tumor sample), and even optimize a selection of appropriate therapies.

A case of sudden death after ultrasound-guided percutaneous alcohol injection of a paraganglioma mis-diagnosed as a peri-renal cyst

Paragangliomas are cromaffin tumors arising from the neural crest cells of parasympathetic or sympathetic ganglia. They are known to be rare causes of sudden death. Here we present the autopsy findings, as well as microscopical and immunohistochemistry study, of a 48-years-old woman who died suddenly after a percutaneous alcohol injection of a peri-renal cyst previously diagnosed as a common complex cyst. She manifested a multiorgan failure, with acute heart failure, systemic and pulmonary vasoconstriction with hypoxia, metabolic acidosis (pH 6.974). It was therefore enacted resuscitation that was ineffective. The autopsy pointed out, close to the upper right renal pole, a cyst characterized by very friable walls and septa, with a thickness of approximately 0.5cm and containing about 75cm(3) of hemoserous fluid. Microscopically, through immunohistochemical examinations, the cyst showed the presence of chromaffin cells, containing enzymes involved in the synthesis of catecholamines, in particular noradrenalin. So, the cause of the death was ascertained in an multi-organ failure caused by a massive release of catecholamines (noradrenaline) from the cyst, identified post-mortem (on the basis of histologic and immunohistochemical examinations) in a noradrenalin-secreting paraganglioma, that remained silent until the cyst ablation.

Role of microenvironment on neuroblastoma SK-N-AS SDHB-silenced cell metabolism and function

In solid tumors, neoplastic cells grow in contact with the so-called tumor microenvironment. The interaction between tumor cells and the microenvironment causes reciprocal metabolic reprogramming and favorable conditions for tumor growth and metastatic spread. To obtain an experimental model resembling the in vivo conditions of the succinate dehydrogenase B subunit (SDHB)-mutated paragangliomas (PGLs), we evaluated the effects of SDHB silencing on metabolism and proliferation in the human neuroblastoma cell line (SK-N-AS), cultured alone or in association with human fibroblasts. Silencing caused a 70% decrease in protein expression, an almost complete loss of the complex specific enzymatic activity, and a significant increase in HIF1α and HIF2α expression; it thus resembled the in vivo tumor cell phenotype. When compared with WT SK-N-AS cells, SDHB-silenced cells showed an altered metabolism characterized by an unexpected significant decrease in glucose uptake and an increase in lactate uptake. Moreover, silenced cells exhibited a significant increase in cell proliferation and metalloproteinase activity. When co-cultured with human fibroblasts, control cells displayed a significant decrease in glucose uptake and a significant increase in cell proliferation as compared with their mono-cultured counterparts. These effects were even more evident in co-cultured silenced cells, with a 70% decrease in glucose uptake and a 92% increase in cell proliferation as compared to their mono-cultured counterparts. The present data indicate for the first time, to our knowledge, that SDHB impairment causes metabolic and functional derangement of neural-crest-derived tumor cells and that the microenvironment, here represented by fibroblasts, strongly affects their tumor metabolism and growth capacity.

Malignant Vagal Paraganglioma

Paragangliomas are rare, typically benign neuroendocrine tumors that represent a small portion of head and neck tumors. A small percentage of these are known to have malignant potential. They arise from the carotid body, jugular bulb or vagus nerves. There is limited literature discussing the management of malignant vagal paragangliomas. We present a case of a 25 year old female with a left malignant vagal paraganglioma. The following case presentation will describe the presentation, classic radiologic findings, and management of a malignant vagal paraganglioma along with a review of the literature.

Anesthetic management for resection of para-aortic paraganglioma and unexpected aortic resection: A case report

Paragangliomas account for 15-20% of pheochromocytomas derived from chromaffin cells and secretes catecholamines. It has a high mortality rate due to hypertension and challenging anesthetic management. The present report is of a case of the successful management of paraganglioma resection with unexpected aortic resection. The patient presented for paraganglioma resection. The blood pressure (BP) was well controlled with α blockade followed by β blockade prior to surgery. The patient was under general anesthesia, with multiple intravenous lines, catheters and an arterial line. Induction was achieved by the administration of narcotic and volatile agents. During the procedure, the aorta was found to require resection in order to complete the tumor resection. The BP changed markedly with clamping and unclamping, tumor vein ligation and tumor resection. The increased BP due to catecholamine release and unclamping was controlled with phentolamine, nitroprusside, esmolol and labetolol. Drops in BP due to tumor vein ligation and clamping were managed with norepinephrine and vasopressin. With close communication and monitoring, the surgery on the patient was successfully completed and the patient was discharged days later in a hemodynamically stable condition. The diagnosis was further confirmed by pathology. This was a challenging case of paraganglioma resection with unexpected aortic resection. The success achieved suggests that the resection of paraganglioma and an aortic segment requires delicate anesthetic management. The key are α blockade and β blockade as necessary to control BP pre-operatively, frequent communication between the anesthesiologist and surgeons, intra-operative intervention in excess catecholamine release with phentolamine, nitroprusside and labetalol prior to tumor removal, and vasopressin for catecholamine deficiency when clamping or subsequent to tumor removal. It is a delicately orchestrated process requiring team work.

A dopamine responsive nano-container for the treatment of pheochromocytoma cells based on mesoporous silica nanoparticles capped with DNA-templated silver nanoparticles

A novel DA responsive delivery system was developed for the treatment of pheochromocytoma cells based on MSNs capped with DNA-templated AgNPs.

Incidentally detected inoperable malignant pheochromocytoma with hepatic metastasis treated by transcatheter arterial chemoembolization

Malignant pheochromocytoma (PCC) is a rare condition. Although the liver is the second most frequent site of metastasis in malignant PCC, no definite treatments have been established. Herein, we report a case of liver metastasis of PCC that was successfully treated by transcatheter arterial chemoembolization (TACE). A 69-year-old man was admitted to the Department of Gastroenterology for evaluation of an incidental hepatic mass in August 2013. He had undergone right adrenalectomy in May 2005 and PCC had been confirmed on the basis of histopathological findings. Liver biopsy was performed, and metastatic PCC was diagnosed. The lesion appeared inoperable because of invasion of the portal vein and metastases in the lymph nodes along the hepatoduodenal ligament. Thus, TACE was performed instead. After TACE, symptoms including dizziness and cold sweating improved, and the patient's serum catecholamine levels decreased. On the basis of this case, we believe that TACE may be a useful treatment for liver metastasis in malignant PCC.