SDHB mutated paraganglioma imitating thyroid tumor: A case report and review of literature

Abstract

Paragangliomas of the head and neck are uncommon tumors arising from parasympathetic ganglia. Paragangliomas are mostly asymptomatic and may manifest as palpable mass of neck. The morphologic features are non-specific and comparable to the other neuroendocrine tumors. Most of hereditary cases are associated with alterations in genes of succinate dehydrogenase (SDH). SDHA and SDHB immunohistochemistry is considered as reliable screening method to detect tumors with genetical alterations. Of note, SDHB mutated paragangliomas have the highest risk of local recurrence, distant metastasis and the development of other tumor phenotypes, which are associated with mutation. Therefore, active surveillance of patients and early surgical treatment are essential. In contrast, SDHB mutated head and neck paragangliomas was considered as completely benign tumors, although, the latest literature describes more controversial cases, which may increase awareness. Here, we present a rare case of 21 years old female with asymptomatic neck paraganglioma, which was unexpectedly diagnosed after pathological and immunohistochemical testing of removed thyroid gland and showed unusual immunohistochemical variation for SDH mutation.

Case report: Intraoperative frozen section analysis of Thyroid paraganglioma

“…Lack of tyrosine hydroxylase results in clinically asymptomatic thyroid PGL. Additionally, thyroid PGL is significantly correlated with mutations in succinate dehydrogenase ( 3 ), and a large percentage of hereditary PGL is a result of susceptible gene mutations in the succinate dehydrogenase complex ( SDH x; including SDHA , SDHB , SDHC , SDHD ), TMEM127 , or MAX ( 4 ). SDHB mutations are important because these are strongly associated with the malignant behavior of PGL ( 5 , 6 ).…”