%0 Journal Article %T Primary Undifferentiated Pleomorphic Sarcoma of the Colon Mesentery %A Dong Baek Kang %A Joo Hyun Lee %A Won Cheol Park %J Archive of "Annals of Coloproctology". %D 2019 %R 10.3393/ac.2018.03.11 %X An undifferentiated pleomorphic sarcoma (UPS), also known as a malignant fibrous histiocytoma in the past, commonly involves the soft tissue of the extremities and the retroperitoneum. However, a primary UPS of the colon mesentery is very rare. A 69-year-old male patient visited our outpatient department for treatment of an enlarged, palpable mass in the right lower quadrant (RLQ). Computed tomography showed a 15-cm multilobulated, heterogeneous, enhanced mass in the RLQ, which we suspected originated from the colon. He underwent a right hemicolectomy, and the pathologic result was a colon mesenteric UPS. We report a rare case of a primary UPS of the colon mesentery and discuss the characteristics of this neoplasm in reference to the literature %K Undifferentiated pleomorphic sarcoma %K Malignant fibrous histiocytoma %K Mesentery %U https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6625777/