A 62-year-old woman whose occult blood test was positive at a medical checkup was referred to our department. Colonoscopy revealed a 10-mm sized type Isp tumor in the lower rectum, We performed endoscopic mucosal resection that revealed the tumor as tub1, T1b (2,000μm), ly0, v1, budding grade 1, HM0 (250μm), and VM0 (500μm). Laparoscopic-assisted low anterior resection of the rectum + D2 dissection was performed. Histopathology revealed no tumor remnant, showing T1b, N0, M0, and Stage I. A CT scan performed 6 months after the operation demonstrated tumors at the bilateral ninth limbs. FDG-PET scan showed abnormal accumulation of FDG (SUVmax7.8) to the tumors. CT-guided biopsy identified the tumors to be well differentiated tubular adenocarcinoma, and metastases of rectal cancer to the ribs were diagnosed.
As bone metastasis from early rectal cancer without associating with liver or pulmonary metastasis is rare, this case is presented, together with a review of the literature.