Foreign body granuloma of activated charcoal.

We present foreign body granulomas induced by activated charcoal from intraperitoneal chemotherapy and mimicked peritoneal metastases in the patients with gastric cancer. On CT, they were manifested as a peritoneal mass or thickening with variable shapes, including oval, round, bizarre, linear and even a molded shape due to where they were lodged, such as the pelvis and paracolic gutter. All the lesions showed high attenuation relative to muscle on the precontrast CT and showed positive findings on PET/CT.