Endocrine Abstracts

Introduction: Paragangliomas are rare neuroendocrine neoplasms originating from the chromaffin cells of the neural crest and projecting from the extra-adrenal paraganglia. For more than 30% of patients with paragangliomas there is a genetic predisposition. According to W.H.O. paragangliomas should be treated as potentially metastatic diseases. We describe the case of a patient with a paraganglioma and a pathogenic variant in the SDHB gene.

Case Presentation: A 17-year-old female patient, presented with sudden, abdominal pain, localized around the umbilicus and reflected in the right iliac fossa. Magnetic resonance imaging (MRI) revealed a 2 cm para-aortic mass with characters of probably lymph node. During surgical excision of the mass, the patient had a hypertensive spike that was treated with an increase in anesthesia. The postoperative course was completely satisfactory. However the biopsy revealed a paraganglioma with GAPP score 7. The patient came to our department for further evaluation and follow-up. Clinical examination revealed no symptoms of catecholamine hypersecretion, nor she reported anything remarkable in the past, except for occasional headaches attributed to an intensive study program. Laboratory testing for catecholamines was within normal range, but due to her young age, additional histological immunohistochemistry testing was requested, where a complete absence of staining for the SDHB subunit was found. Whole Exome Sequencing revealed the presence of the maternally inherited heterozygous variant, c.201-2A>G, in the SDHB gene (NM_003000.3). This variant affects intron 2 acceptor splice site and was classified as Pathogenic according to the ACMG criteria and SDHB variant classification recomendations. To date, 6 family members have been found to be carriers of this variant, presenting no symptoms or pathological imaging, indicating low variant penetrance. The patient is currently free of disease, both according to laboratory and imaging tests (DOTADOC, MIBG), and is being monitored based on the relevant guidelines.

Conclusions: A common location of sympathetic paragangliomas is the abdomen (para-ortically, Zuckerkandl body), and, with few exceptions, they secrete catecholamines. For this reason, it should be included in the differential diagnosis of an intra-abdominal mass, even without obvious symptoms of catecholamine hypersecretion, especially when it comes to young people, in order to carry out the appropriate laboratory test preoperatively. Pathogenic variants in the succinate dehydrogenase (SDH) gene and specifically the SDHB, SDHC and SDHD genes, accounts for approximately 50% of hereditary paragangliomas. The combination of paraganglioma with increased GAPP score and SDHB gene mutation is an important predictor of the possibility of metastases.