An 83-year-old man underwent laparoscopic low anterior resection for rectal cancer of Rs(SM, N1 (1/14), M0 Stage IIIa) 10 months earlier. No abnormalities were found during the post-operative course, but he was referred to the outpatient department due to an abdominal mass, 3.5 cm in diameter, below the navel. The tumor was visualized as a hard mass on ultrasound elastography, and the interior of the tumor mass on contrast-enhanced CT showed lighter contrast. The tumor showed high signal intensity on MRI diffusion-weighted imaging. Aspiration cytology of the tumor was negative. A port site recurrence of rectal cancer after surgery was suspected due to a history of cancer, and thus the mass was resected. On histological examination, an inflammatory granuloma was seen in the rectus abdominis muscle aponeurosis. No foreign body could be confirmed, and a diagnosis of Schloffer tumor was made. A subcutaneous mass of similar size (3.0 cm) appeared suddenly at the port site near the left lower quadrant of the abdomen two months later, and the patient underwent tumor resection of a suspected inflammatory granuloma. This case illustrates the difficulty in differentiating a Schloffer tumor from abdominal wall metastasis of cancer.