Inflammatory 68Ga FAPI-46 Uptake Mimicking a Sister Mary Joseph’s Nodule in a Case of Gastric Signet Ring Cell Carcinoma

Fibroblast activation protein (FAP) is a type II transmembrane protease expressed in cancer-associated fibroblasts (CAF) that constitute a part of the tumor stroma and influence the tumor microenvironment. Although FAP is not expected to be physiologically expressed in noncancer-associated cells, it can be observed in wound healing, arthritis, atherosclerotic plaques, and fibrosis. In this case, we would like to present early-stage 68 Ga FAPI-46 PET/CT inflammation findings at the trocar entry site mimicking the Sister Mary Joseph's nodule in a patient diagnosed with gastric signet ring cell carcinoma.