A 46-year-old man visited the emergency department of our hospital with a 3-day history of anal pain, hemorrhaging, and a slight fever. He had previously been diagnosed with protein C deficiency and was prescribed dabigatran, a direct oral anticoagulant. Contrast-enhanced computed tomography showed severe rectal wall thickening with partial defect of enhancement. In addition, sigmoidoscopy revealed a dusky purplish swollen anorectal mucosa just above the dentate line. He was diagnosed with acute anorectal thrombophlebitis, and anticoagulant therapy with heparin was initiated. To our knowledge, this is the first case report of acute anorectal thrombophlebitis caused by protein C deficiency.
Keywords: acute thrombophlebitis; direct oral anticoagulants; protein C deficiency; venous thromboembolism.