Aggressive fibromatosis of the sigmoid colon: A case report

BACKGROUND Aggressive fibromatosis (AF), also known as desmoid tumor or desmoid-type fibromatosis, is a rare soft tissue neoplasm that can occur in almost any part of the body. Although it is a benign disease, AF is aggressive and infiltrative and has a high recurrence rate after surgery. Common sites for intra-abdominal AF are the small bowel mesentery, retroperitoneum, and pelvis. AF in the colon is extremely rare. CASE SUMMARY Here, we report the first case of sigmoid colon AF, which was accidentally discovered in a 27-year-old woman during laparoscopic myomectomy. Computed tomography confirmed a slightly enhanced mass in the sigmoid colon. Subsequent colonoscopy did not reveal a mass in the colonic lumen, but a suspected external compress was found in the sigmoid colon. Surgical disease involving a gastrointestinal stromal tumor was suspected. The patient underwent laparoscopic exploration, and sigmoidectomy with a negative margin was performed to excise the mass. Postoperative immunohistochemistry revealed that the mass was an AF. The patient recovered well and was recurrence-free at the 30-month follow-up without adjuvant therapy. CONCLUSION AF should be considered in the differential diagnosis of subepithelial colon masses. Radical resection alone can achieve good outcomes.