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.