Adenosquamous carcinoma of the hepatic flexure of colon: a case report.

Adenosquamous carcinoma (ASC) is defined as a very rare subset of colorectal cancer containing both adenocarcinoma (AC) and squamous cell carcinoma (SCC) components. ASC is more aggressive for resulting in a poorer prognosis than AC alone. To date, only few cases were recorded previously. Here, we reported that a 46-year-old woman was caught by abdominal pain and hematochezia for more than 20 days and she visited the emergency room with increasing abdominal pain and vomiting for nearly one day. Physical examination indicated direct tenderness in the navel and lower abdomen distension. Laboratory examinations showed a decreased hemoglobin, increased white blood cell (WBC) count, an elevation of the serum levels of CA19-9 and carcinoembryonic antigen (CEA). Then endoscopic examination revealed a hemicircumferential mass in the ascending colon, which contained a friable and ulcerated lesion that bled easily when touched. Results of biopsy suggested a high-grade intraepithelial neoplasia. Abdominal computed tomography (CT) scanning showed some signs of neoplastic lesion that the wall of the hepatic curvature of the transverse colon is irregularly thicker, the serous surface of the diseased intestinal canal is slightly thicker, and multiple peripheral lymph nodes are enlarged. Furthermore, the multidisciplinary team (MDT) meeting thought laparoscopic right colectomy accompanied with lymphadenectomy was suitable because the clinical stage was at least stage IIIB. The post-operative pathological examination demonstrated that the tumor was composed of AC (positive for CDX-2 and CK20) and SCC (positive for CK5/6 and P63) components. Accordingly, this case was diagnosed as ASC of Stage IIIC (pT4N2M0) and the adjuvant chemotherapy FOLFOX was recommended, while unfortunately the patient refused it for personal reasons. In conclusion, radical resection remains the major treatment for colon ASC, CT scan and endoscopic examination and biopsy are useful for this pre-operative diagnosis. This case promotes the understanding of colon ASC and provides a basis for its clinical diagnosis and treatment.