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

PURPOSE: To demonstrate the imaging characteristics of neuroendocrine tumors (NETs) of the pancreas in patients with von Hippel–Lindau (VHL) disease to establish diagnostic criteria. MATERIALS AND METHODS: 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. RESULTS: 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 (≥3.0 cm) tumors; howev...