Neuroendocrine tumors of the pancreas in von Hippel-Lindau disease: spectrum of appearances at CT and MR imaging with histopathologic comparison.

Abstract

To demonstrate the imaging characteristics of neuroendocrine tumors (NETs) of the pancreas in patients with von Hippel-Lindau (VHL) disease to establish diagnostic criteria. Twenty-five patients with VHL disease and 29 surgically confirmed pancreatic NETs were included. Screening computed tomographic (CT) and/or magnetic resonance (MR) imaging findings were reviewed, and tumor number, diameter, growth rates (doubling time), location, presence of metastatic disease, and attenuation or enhancement properties were determined. Eighteen of 29 (62%) pancreatic NETs were smaller than 3.0 cm in diameter and enhanced homogeneously on contrast material-enhanced CT and MR images. No tumor smaller than 3.0 cm metastasized. Tumors 3.0 cm or larger (11 [38%] of 29) more often enhanced heterogeneously, and two of 11 were associated with hepatic metastases. Smaller (<3.0 cm) tumors displayed longer mean doubling times (mean, 927 vs 351 days) than did larger (> or =3.0 cm) tumors; however, there was considerable overlap. Fifteen (52%) tumors were located in the pancreatic head; eight (28%), in the tail; and six (21%), in the body. Ten (40%) patients with pancreatic NETs had associated pheochromocytomas, and 22 (88%) had no or mild pancreatic cystic disease, which is substantially more than the general population of patients with VHL disease. Pancreatic NETs in VHL have characteristic features at CT and MR imaging: Most are small, located in the pancreatic head, and enhance homogeneously. Tumors larger than 3.0 cm are prone to metastasize and enhance heterogeneously.