Adenosquamous Carcinoma of the Ascending Colon: A Case Report and Review of the Literature
A 43-year-old female presented a large colon mass during colonoscopy for screening at another hospital. The mass was circumferential and ulcerofungating, and was located at the middle ascending colon (). The result of microscopic examination was reported as a moderately-differentiated adenocarcinoma, and she came to our hospital for surgical treatment. She only had constipation and had not shown any other specific symptoms or signs related with the cancer. There was no significant past medical history and no family history of colorectal cancer. The patient's serum carcinoembryonic antigen level was 1.22 ng/mL, and her serum hemoglobin level was 10.9 g/dL. There was no significant abnormal result among initial laboratory findings. A computed tomographic scan of the abdomen identified a short, segmental, circumferential, irregular wall thickening on the ascending colon with enlargement of four pericolonic lymph nodes (). There was no evidence of distant metastasis on the positron emission tomographic scan.\nA laparoscopic right colectomy with lymphadenectomy was done, and intraperitoneal organs, including the liver, did not show any abnormal appearance on inspection. Pathologic examination of the colon specimen revealed an ulcerofungating mass, measuring 6.0 cm × 5.0 cm × 1.0 cm (). It had invaded the periserosal fat layer and contained both of a moderately-differentiated adenocarcinoma and a well-differentiated squamous cell carcinoma on microscopic examination (). Finally, the mass was diagnosed as an adenosquamous carcinoma of stage IIIB (T3 N2a M0) according to the 7th edition of the colon and rectum cancer staging system published by the American Joint Committee on Cancer. After the operation, she received adjuvant chemotherapy six times with the FOLFOX4 (oxaliplatin, leucovorin, and fluorouracil) regimen. There has been no evidence of tumor recurrence during the 10 months since the completion of adjuvant chemotherapy.