Periampullary neuroendocrine tumor with large intracellular mucin globules, an amphicrine tumor?

Abstract

Amphicrine carcinoma is a rare type of mixed adenoneuroendocrine carcinoma in which both exocrine and endocrine components are co-expressed in the same tumor cells. We report a case of a 57 year old man with a complex cystic and solid periampullary mass which shows a misleading poorly differentiated morphology. The tumor cells are positive for neuroendocrine markers with some cells showing large intracytoplasmic mucin. Additionally, CEA immunostain is weakly, but diffusely positive in the same tumor cells. The tumor may represent an amphicrine carcinoma, however, it has been reported that neuroendocrine cells may show aberrant mucin production. To what extent of mucin production should the tumor have to be considered as amphicrine is the question without answer, and currently the diagnostic criteria for amphicrine carcinoma have not been well established.