The patient was a 67-year-old man. In 2017, he underwent sigmoid colostomy with double orifices for treating obstructive lower advanced rectal cancer. After preoperative chemoradiation therapy, low anterior resection of the rectum, D3 lymph node dissection, and diverting ileostomy were performed. The postoperative pathological diagnoses were ypT3, ypN0, ycM0, and ypStage II. Postoperative adjuvant chemotherapy with UFT/LV was administered for 6 months. In 2019, computed tomography revealed two masses shadow, on the inferior surface of the liver and caudal to the mid-gastric region, indicating multiple peritoneal dissemination recurrence. A total of 21 courses of FOLFOX plus panitumumab were administered, while the mass continued to shrink for approximately 14 months. No other new lesions developed, and with informed consent, closure of the ileostomy and peritoneal dissemination resection were performed in 2021. Postoperative pathological examination revealed that what was considered a peritoneal dissemination on the inferior surface of the liver was a desmoid tumor primary to the ligamentum teres hepatis. There are few reports of desmoid tumors occurring after surgery for colorectal cancer or primary desmoid tumors of the ligamentum teres hepatis, and it is extremely difficult to differentiate them from postoperative cancer recurrence.