Papillary Cystadenoma of the Mesorectum in von Hippel-Lindau Disease

A 22-year-old woman with von Hippel-Lindau (VHL) disease presented with a hypervascular mesorectal mass (44×38 mm). Imaging revealed features consistent with VHL-associated cystadenomas, such as a sponge-like appearance, high signal intensity on T2-weighted images, and early enhancement. The possibility of a highly malignant tumor was excluded based on high ADC values, low FDG uptake, and minimal size change. Biopsy confirmed benign papillary cystadenoma, similar to other VHL-associated tumors. It is important to be aware that papillary cystadenomas can arise in unexpected locations in patients with VHL disease, and that recognizing characteristic imaging and pathologic features could facilitate early diagnosis and clinical decision-making, even if tumors arose in atypical sites.