2023 Volume 38 Issue 4 Pages 271-278
Patient 1 was a 64-year-old woman who underwent evaluation due to weight loss. A 42mm diameter cystic lesion was found in the tail of the pancreas, and a 2mm-thick rim was enhanced in a contrast-enhanced CT scan arterial phase. In the resected specimen, the tumor was covered with a fibrous capsule, and there were no nodules, necrosis, or blood pooling within the cyst. A neuroendocrine tumor (NET) G1 was found inside the capsule, characteristic of so-called "purely cystic pancreatic neuroendocrine neoplasm (PNEN)". Patient 2 was an 80-year-old man who underwent evaluation for worsening diabetes. There was a 2mm diameter cyst in the tail of the pancreas, which was high-intensity on diffusion-weighted MRI and a 1-2mm-thick rim was enhanced by contrast-enhanced EUS (CE-EUS). The resected specimen showed a 5mm diameter cystic tumor with NET G1 proliferation on the inner surface of the fibrous capsule. These findings had the same histological structure as Patient 1. In Patient 2, CE-EUS observation was diagnostically useful, and EUS may have provided visualization of a very early purely cystic PNEN.
