ACINAR-ISLET CELL-CARCINOMA PRESENTING AS INSULINOMA

A case of acinar-islet cell carcinoma presenting as insulinoma is repo rted. The patient was a 28-year-old man who presented with two convuls ive episodes, Fajans' index [immunoreactive insulin (IRI; mu U/ml / gl ucose mg/dl)] and Turner's [IRI (mu U/ml) x 100 / glucose (mg/dl)] - 3 0] index were high (2.8 and 308, respectively), as were serum proinsul in levels (550 pg/ml). Abdominal computed tomography and angiography r evealed a highly vascular tumor in the pancreatic tail and several sim ilar tumors in the liver. Histologic features of a biopsy specimen fro m a hepatic tumor were those of a malignant pancreatic endocrine tumor . Insulin secretion by the liver metastases was confirmed by venous sa mpling alter arterial stimulation with calcium. These findings led us to diagnose malignant insulinoma with liver metastases. Serum levels o f alpha-fetoprotein and trypsin were markedly elevated, to 2234 ng/ml (normal < 10) and 22 000 ng/ml (normal < 460) respectively, and these levels continued to rise with further growth of the liver metastases, Immunohistochemically, the metastatic liver tumor specimen was positiv e for alpha-fetoprotein, alpha 1-antichymotrypsin, chromogranin A, and neuron-specific enolase. These findings of amphicrine features in the tumor were indicative of acinar-islet cell carcinoma that produced al pha-fetoprotein and trypsin in addition to insulin.