Cytomegalovirus Colitis and Colon Adenocarcinoma: A Case of Unusual Co-existence

The possible association of Cytomegalovirus (CMV) with human colorectal adenocarcinomas was first reported in 1978 by Huang and Roche, who detected CMV DNA in 4 of 7 colonic adenocarcinomas by membrane complementary Ribonucleic Acid-Deoxyribonucleic Acid (RNA-DNA) hybridisation. CMV earns its name from the characteristic cytomegalic appearance of intranuclear inclusions in infected cells, which include endothelial cells, histiocytes, macrophages, and epithelial cells. The most common site of CMV infection in the gastrointestinal tract is the colon (55%), followed by the sigmoid colon and rectum (35%) and the gastric antrum (25%). Here, a middle-aged female presenting with pain in the lower abdomen, which was insidious in onset and gradually progressive. Ultrasonography revealed a large intestine dilated and filled with multiple air-fluid levels, indicating bowel obstruction. Multidetector Computed Tomography (MDCT) showed circumferential wall thickening involving the distal half of the transverse colon and descending colon. The case was subjected to laparotomy. The resected segment of the colon was sent for histopathological evaluation, and microscopic examination showed adenocarcinoma and many mucosal ulcers, which on keen observation revealed viral inclusions. The diagnosis of colon adenocarcinoma, with a pathological staging of pT2N0Mx with CMV infection, was rendered. CMV infection was confirmed by immunohistochemistry. The patient was on post-surgery chemotherapy and receiving ganciclovir. On follow-up, the patient was recovering fine. Histopathology examination and IHC remain the gold standard in diagnosing CMV, and the concurrent occurrence of colitis and carcinoma should be kept in mind to assist in proper management.