Pancreatic calcifications in malignant islet cell tumors.

Of 623 cases of malignant pancreatic tumor seen at University of Chicago hospitals over the last 30 years, 23 cases of malignant islet cell tumor were found (8 additional cases were found in the literature). Calcification, found in 2 of these cases, was characteristically discrete and nodular (calcifications found in chronic pancreatitis are typically diffuse, multiple, and punctuate). At least 7 of the 10 cases of islet cell tumor with calcification were malignant. Slow growth of the tumor, with calcified metastases, strongly suggests the diagnosis of malignancy; this combination of findings has been established in 3 cases. In 73 cases of benign islet cell tumor, no calcifications were found.