Case of the Very Rare Gallbladder Paraganglioma

Gallbladder paraganglioma is a very rare condition, and only a few cases have been reported in the literature. Herein, we present and discuss the clinical and radiological findings of a 72-year-old woman who complained of heaviness, pain, and on and off watery discharge from the left ear for 1 year and reduced hearing in both ears. She was thoroughly investigated radiologically where multiple paragangliomas were found with the discovery of the very rare gallbladder paraganglioma. There is a need to realize the importance of thorough radiological evaluation in cases of head and neck paraganglioma to look for more such lesions in the body for early identification of patients with familial paraganglioma syndromes. With this practice, gene mutation carriers can be identified early in the course of their disease and brought to surgical attention before their disease becomes extensive and potentially life-threatening.

Head and Neck Paragangliomas—A Genetic Overview

Pheochromocytomas (PCC) and paragangliomas (PGL) are rare neuroendocrine tumors. Head and neck paragangliomas (HNPGL) can be categorized into carotid body tumors, which are the most common, as well as jugular, tympanic, and vagal paraganglioma. A review of the current literature was conducted to consolidate knowledge concerning PGL mutations, familial occurrence, and the practical application of this information. Available scientific databases were searched using the keywords head and neck paraganglioma and genetics, and 274 articles in PubMed and 1183 in ScienceDirect were found. From these articles, those concerning genetic changes in HNPGLs were selected. The aim of this review is to describe the known genetic changes and their practical applications. We found that the etiology of the tumors in question is based on genetic changes in the form of either germinal or somatic mutations. 40% of PCC and PGL have a predisposing germline mutation (including VHL, SDHB, SDHD, RET, NF1, THEM127, MAX, SDHC, SDHA, SDHAF2, HIF2A, HRAS, KIF1B, PHD2, and FH). Approximately 25–30% of cases are due to somatic mutations, such as RET, VHL, NF1, MAX, and HIF2A. The tumors were divided into three main clusters by the Cancer Genome Atlas (TCGA); namely, the pseudohypoxia group, the Wnt signaling group, and the kinase signaling group. The review also discusses genetic syndromes, epigenetic changes, and new testing technologies such as next-generation sequencing (NGS).