Журнал исследований опухолей и отчетов

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Primary Mixed Adenoneuroendocrine Carcinoma (MANEC) of Gallbladder, Report of Two Cases with Different Histologic and Immunohistochemical Features

Cyrus Parsa, Robert Orlando, Krishna Narayanan, David Duate and Shaun Webb

Since implementation of immunohistochemistry, the occurrence of neuroendocrine cells in adenocarcinomas of gastrointestinal tract has been well documented and is not uncommon. The mixture of neuroendocrine carcinoma and adenocarcinoma (MANEC), where each represents at least 30% of the neoplasm, is however very uncommon and occurs mostly in the stomach, appendix, and large intestine. Their occurrence in the gallbladder, as the primary site, is exceptionally rare. We present two elderly patients, one male and one female with clinical manifestations of cholecystitis. The cholecystectomy specimens from these patients revealed MANEC. In one patient, the epithelial component was conspicuously papillary and well-differentiated. In our second case, the epithelial component was variably poorly differentiated carcinoma with mixed neuroendocrine collision features. In this paper we describe the clinicopathologic features of these two cases with emphasis on differences in their gross, histologic, and immunohistochemical findings. These differences may be attributed to the proposed varied pathways for the origin of neuroendocrine cells in the gallbladder.