Ovarian-like stroma in an invasive mucinous cystadenocarcinoma of the pancreas positive for inhibin. A hint concerning its possible histogenesis.

A female patient with a mucinous cystadenocarcinoma originating from a mucinous cystadenoma of the pancreas is presented. The cystic tumour was diagnosed 3 years before and was treated with interventional external and internal surgical drainage before radical resection was accomplished by left hemipancreatectomy. Histology showed simultaneous occurrence of mildly dysplastic and invasive malignant epithelium. Immunohistology revealed inhibin-positive cells in the ovarianlike stroma of the tumour. The demonstration of ovarian-like stroma positive for inhibin suggests that this could be a hamartoma with dispersed sex-cord stroma, which would explain the predominance of the female gender in mucinous cystic tumours of the pancreas.