Abstract
A 76-year-old man consulted our hospital for further examination of a protruding gastric lesion that had been detected in the upper gastrointestinal series. Esophagogastroduodenoscopy revealed extrinsic compression of the posterior wall of the gastric body. US demonstrated a cystic lesion with an irregularly thickened capsule, in which flow signal was detected by Doppler image. The capsule of the tumor showed almost the same staining pattern as the surrounding pancreatic parenchyma in contrast enhanced CT. Endoscopic ultrasound delineated the irregular capsule of the tumor and revealed a swollen regional lymph node. Laboratory findings, including tumor markers and hormonal data, showed normal findings. Distal pancreatectomy with splenectomy was performed based on a preoperative diagnosis of pancreatic neuroendocrine tumor as cystic degeneration with regional lymph node metastasis. The tumor was 40 mm in size, well demarcated, and solid with cystic degeneration. As tumor cells were immunohistochemically positive for chromogranin A and synaptophysin, the lesion was diagnosed as a pancreatic neuroendocrine tumor. An irregularly thickened capsule and abundant vascularity are useful findings to differentiate neuroendocrine tumors with cystic degeneration from other ordinary cystic lesions.
