A case of mixed acinar-endocrine carcinoma of the pancreas discovered in an asymptomatic subject

A 50-yr-old Japanese man was found to have a hypoechoic mass 3 cm in diamet er in the pancreatic head on an ultrasonography (US) examination without sy mptoms. A computed tomography (CT) scan demonstrated a 3-cm solid mass in t he pancreatic head, and it was more clearly delineated as a low-density are a on enhanced CT. Angiography showed a tumorlike stain, 3 cm in size, in th e pancreatic head. The preoperative diagnosis was "special type of pancreat ic tumor such as acinar cell carcinoma or non-functioning islet cell tumor. " The patient was treated by pylorus-preserving pancreatoduodenectomy. Hist ological, immunohistochemical, and electron-microscopic studies of the surg ical specimen led to a definitive diagnosis of a mixed acinar-endocrine car cinoma. The patient is currently well, with no signs of tumor recurrence, 1 8 mo after the operation. Our search of the Japanese and English-language l iterature retrieved only 15 well-documented cases of mixed acinar-endocrine carcinoma. Imaging in the reported cases revealed features of either acina r cell carcinoma or islet cell tumor, or both, which can may be detected ev en in small tumors more easily than conventional invasive ductal carcinoma of the pancreas because the detectability of this rare tumor on US and CT s eems to be good.