Pancreatic lipoma: An incydentaloma which can resemble cancer – analysis of 13 cases studied with CT and MRI

BACKGROUND: The purpose of this article is to present computed tomography (CT) and magnetic resonance imaging (MRI) findings of rare pancreatic lipomas. MATERIAL/METHODS: The analysis covered 13 patients (7 men and 6 women, aged 47–88, average: 65.6 years), with 13 pancreatic lipomas, whose cases constituted the basis for 10 contrast-enhanced CT and 5 MRI studies. RESULTS: Lipomas measured from 6 mm to 32 mm (average 12.8 mm) and were located in the pancreatic head (n=7), body (n=2), tail (n=3) and uncinate process (n=1). Most lesions (n=11) were homogenous, well-circumscribed. On contrast-enhanced CT scans, macroscopic fat (<−30 HU) was present in 9 lipomas. In one case (10 mm lesion) the density was −20 HU and the lesion was poorly circumscribed with septations, which altogether made it difficult to precisely characterize its contents. On MR scans fat was demonstrated in all studied cases (n=5). CONCLUSIONS: Lipomas are rare, small, homogenous and well-circumscribed pancreatic tumours. The most important feature, decisive for the diagnosis and distinguishing them from pancreatic carcinoma, is detection of fatty tissue on CT and MR scans. In these cases differential diagnosis includes other rare fatty tumours of the pancreas (focal fatty infiltration, teratoma, liposarcoma).