The patient was a 71-year-old woman diagnosed with mesenteric phlebosclerosis(MP)2 years earlier. CT performed to investigate her abdominal pain revealed an ascending colon obstruction. Colonoscopy(CS)revealed MP extending to the ascending colon hepatic flexure with stenosis and a cecal tumor(biopsy tub1). Although the cancerous lesion itself was potentially curable by endoscopic treatment, it was surgically resected because of the ascending colon stenosis caused by the MP that had also caused intestinal obstruction. Intraoperative findings revealed wall thickening and stiffening from the cecum to the ascending colon hepatic flexure. Postoperative pathological examination revealed cecal carcinoma pTis, N0, M0, pStage 0. The background mucosal tissue was consistent with MP, but no findings suggested a relationship between the MP and tumor. Although the relationship between MP and carcinogenesis is unknown, and no such relationship was identified in this case, we report this case because a further accumulation of cases of MP and carcinoma is necessary, considering the rarity of MP itself and the non-negligible number of cases with carcinoma.