A 40-year-old man with no previous history of abdominal surgery or noteworthy family history presented to our hospital because of a palpable abdominal mass. Abdominal CT revealed a 9 cm diameter mass in the mesocolon. The differential diagnosis included desmoid tumor, and right hemicolectomy with partial resection of the pancreas head and duodenum was performed. Pathologically, the tumor cells were negative for S-100, c-kit, CD34, and desmin but partially positive for a-SMA and slightly for b-catenin. From these findings, desmoid tumor of the mesocolon was diagnosed. Invasion of the pancreas was also found. Desmoid tumor is pathologically benign, but because of its malignant-like characteristics, such as direct invasion and local recurrence, it is treated as a malignant tumor. Desmoid tumors are associated with familial adenomatous polyposis coli and Gardner syndrome, or they arise in patients who have a history of laparotomy or antecedent trauma. In this paper, we report a rare case of resected sporadic desmoid tumor in the mesocolon with pancreatic invasion, together with a review of the literature.