Serous Microcystic Adenoma of the Pancreas: Cytologic and HistologicFeatures. A Case Report

Overview

Cytologic and histologic features in a case of serous microcystic adenoma of the pancreas ina 61-year-old female are presented. In fine-needle aspiration materials, epithelial cells arrangedsingly, in small clusters and in monolayer sheets were found. The neoplastic cells had round tooval nuclei with finely distributed chromatin and inconspicuous nucleoli. Nuclear atypia andmitoses were not seen. The cytoplasm was moderately abundant and finely granular.Histologically, the encapsulated tumor was composed of multiple small cysts lined by a singlelayer of flat to cuboidal cells. The tumor cells contained clear cytoplasm with glycogen andcentrally located round to oval nuclei with inconspicuous nucleoli without any atypia. Mitoseswere absent. The intervening stromal septa were hypocellular. Immunohistochemically, the tumorcells revealed diffuse positivity of cytokeratins and epithelial membrane antigen. Proliferativeantigen Ki-67 was positive only in sporadic cells. No immunoreactivity for vimentin, carcinoembryonalantigen and S-100 protein was found. Chromogranin A and synaptophysin were expressedonly in Langerhans’ islets in the tumor capsula.In differential diagnosis, it is important to distinguish serous microcystic adenoma mainly fromlymphangioma, cavernous hemangioma, serous cystadenocarcinoma, mucinous cystadenoma orcystadenocarcinoma, solid and pseudopapillary epithelial tumour, acinar cell cystadenocarcinoma,renal cell carcinoma and mesothelioma.

Key words:
serous microcystic adenoma of the pancreas – cystic tumours – histology – fine-needleaspiration cytology