Gangliocytic paraganglioma presenting as a large pedunculated periampullary duodenal POLYP

Abstract

A 52-year-old female presented with gastrointestinal bleeding caused by a polypoid tumour of the ampulla of Vater which clinically was suspected to be a carcinoma. A CT guided biopsy showed a tumour with morphology and immunophenotype in keeping with a ‘neuroendocrine tumour’. Subsequent pancreatico-duo-denectomy revealed a large 35 mm periampulary polyp. Histological and ultrastructural examination of the polyp showed features of a gangliocytic paraganglioma. The ganglion cells were present focally in a nested arrangement resembling a pattern of paragangliomas. Gangliocytic paragangliomas are rare solitary, periampullary tumours of the duodenum usually not exceeding 20 mm in diameter, which occur without age or sex predilection. Histologically, they consist of three cell types, namely epithelioid, ganglion cells and spindle cells admixed in various proportions with immunohisto-chemical and ultrastructural evidence of neuroendocrine differentiation. Gangliocytic paragangliomas may pose diagnostic difficulties in small endoscopic biopsies, as not all three components may be sampled. The ganglion and epithelioid cells can appear cytologi-cally atypical which, combined with disorganised growth pattern, inflammation and necrotic debris, may lead to erroneous diagnosis of malignancy. It is of paramount importance to notice that desmoplasia and mitoses are absent. Demonstration of dual expression of epithelial and neuroendocrine markers assists to arrive at correct diagnosis.