Abstract: Abstract: Myofibroblastic sarcoma (MS) is a low-grade malignant soft tissue tumor of mesenchymal origin with a low clinical incidence. This paper presents a case of MS originating from the small intestinal mesentery. MRI revealed a mass with heterogeneous signal intensity in the lower abdomen and pelvic cavity, which exhibited partial cystic changes and hemorrhage. The initial imaging diagnosis suggested a malignant tumor of peritoneal, retroperitoneal, or adnexal origin. Postoperative pathological results confirmed MS of the small intestinal mesentery, and the patient demonstrated a favorable recovery during the follow-up period. This case report analyzes the imaging features and key considerations of the disease to improve diagnostic accuracy.