FDG-PET/CT findings of peritoneal lymphomatosis.

: Peritoneal lymphomatosis (PL) is an extensive lymphomatous infiltration of the intraperitoneal portion of the subperitoneal space, which is a rare presentation of lymphoma. Using CT or MRI findings alone, it is difficult to differentiate between lymphomatosis, carcinomatosis, and other pathological entities.We experienced two PL cases and herein report the FDG-PET/CT findings. High FDG uptakes were found in omental and peritoneal infiltration, gastric wall involvement, and lymph node involvement in the epiphrenic region, although retroperitoneal lymph node involvement was absent. Systemic abnormal FDG uptakes suggested PL rather than carcinomatosis, and FDG-PET/CT findings were useful for the diagnoses.