HER2-Negative Schnitzler Metastasis to the Rectum Detected Using 18 F-FDG PET/CT.

Gastric carcinoma metastasis occurs via hematogenous, lymphatic, or peritoneal seeding. We describe FDG PET/CT findings of Schnitzler metastasis to the rectum in a 39-year-old woman who had radical gastrectomy for signet ring gastric adenocarcinoma 2 years prior. FDG PET/CT demonstrated increased homogeneous round activity in the inner layer of rectal wall. Occult metastases of gastric carcinoma tend to be difficult to treat and have a poor prognosis. However, in some cases, FDG PET/CT might be beneficial for early detection and diagnosis of Schnitzler metastasis.