Case of adenosquamous carcinoma of the ascending colon

Adenocarcinoma accounts for most of the malignant tumors originating from the colon, whereas adenosquamous carcinoma is rare, accounting for about 0.1% of all colon cancers. We present herein a case of adenosquamous carcinoma of the ascending colon. The patient was a 94-year-old woman who presented with a chief complaint of lower abdominal pain. A barium enema examination and lower gastrointestinal endoscopy showed a type 3 tumor in the ascending colon, and a biopsy confirmed the diagnosis of adenosquamous carcinoma. Right hemicolectomy was performed, and the tumor was diagnosed as a stage III advanced colon cancer. The patient had postoperative aspiration pneumonia and died 35 days after surgery. A search of Japanese literature over the past 25 years yielded 70 patients with adenosquamous carcinoma of the colon, and the clinicopathological features are discussed herein.