Paraganglioma of the Vagina Associated With Germline SDHB Mutation: Report of a Case With Review of the Literature.

Paragangliomas are rare neuroendocrine neoplasms in the vagina, and their molecular pathogenesis has not been documented. We report a case of vaginal paraganglioma in a 15-yr-old adolescent girl who presented with irregular heavy menses and anemic symptoms. Examination under anesthesia revealed a polypoid mass of 3 cm size in the left anterior vaginal wall, which was resected piecemeal. Histology showed a circumscribed nodular tumor with typical nested morphology of paraganglioma and no significant nuclear atypia. Immunohistochemically the tumor cells were diffusely positive for synaptophysin and chromogranin while being negative for cytokeratin, accompanied by S100-positive sustentacular cells. SDHB immunohistochemistry demonstrated the absence of cytoplasmic staining in the tumor cells with preserved staining in sustentacular cells, raising the possibility of a germline mutation in the genes encoding subunits of succinate dehydrogenase. Sanger sequencing for all the exons and exon-flanking intronic regions of the SDHB gene revealed no mutation, but further investigation with multiplex ligation-dependent probe amplification identified a heterozygous deletion of exon 1 of the SDHB gene in the patient and her mother, confirming the diagnosis of SDHB-related hereditary paraganglioma-pheochromocytoma syndrome. The patient had no evidence of disease upon imaging surveillance and follow-up for 56 mo. A review of the published cases of vaginal paraganglioma seems to suggest a relatively young age of presentation, commonly encountered as incidental findings in asymptomatic patients or presenting with abnormal vaginal bleeding. The association between vaginal paraganglioma and germline SDHB mutation has not been reported. We believe this case illustrates the clinical significance of SDHB immunohistochemistry and genetic testing for this rare vaginal neoplasm.