A primary malignant fibrous histiocytoma (MFH) is a soft tissue sarcoma of mesenchymal origin. A primary MFH occurs most commonly in the extremities and the trunk in adults, but rarely in the alimentary tract. We report a case of MFH of the mesoappendix in a 49-year-old male who presented with a periappendiceal abscess. To the best of our knowledge, this is the first report of MFH in the large intestinal tract, including the appendix, in Korea. The patient recovered well after a right hemicolectomy and was given adjuvant chemotherapy.