MRI of pancreatic islet cell carcinoma.

Abstract

The purpose of this study is to report the spectrum of MR findings of pancreatic islet cell carcinoma. The MR scans of 33 patients with islet cell carcinoma were retrospectively reviewed. Magnetic resonance detected the primary tumor in 21 of 27 patients (78%) who had not had prior resection of their primary tumor. Mean tumor diameter was 7.1 cm (range 3.5-13.0 cm). In all patients, the primary tumor on T1-weighted images (TR/TE = 250/15) was of signal intensity equal to or lower than that of the adjacent normal pancreas. The primary tumor on T2-weighted images (TR/TE = 2,000/> or = 100) was of signal intensity the same as or higher than fat in 18 of 21 patients (86%) and had mixed signal intensity in the other 3 (14%). Hepatic metastases were found in 28 of 33 patients (85%). Liver metastases were categorized as "usual" (variably circumscribed, homogeneous lesions of medium signal intensity on T2-weighted images) in 19 of 28 patients (68%), necrotic in 8 of 28 (29%), hemorrhagic in 3 of 28 (11%), and calcified in 1 of 28 (4%). Extrahepatic metastases were found in 18 of 33 patients (55%). We conclude that MRI is an excellent modality for the diagnosis and routine follow-up of patients with islet cell carcinoma.