Colorectal perforation in cytomegalovirus colitis during chemotherapy for metastatic colorectal cancer: a case report.

INTRODUCTION: Cytomegalovirus (CMV) infections often occur as opportunistic infections among immunocompromised hosts. We report a case of CMV colitis that resulted in colonic perforation in a patient undergoing chemotherapy for more than 2 years for metastatic colorectal cancer (mCRC). PRESENTATION OF CASE: A 61-year-old man receiving long-term chemotherapy for mCRC presented with persistent diarrhea and anorexia. Colonoscopy revealed ulcerating colorectal lesions. Following admission, he exhibited signs of peritoneal irritation and bloody stools. Computed tomography demonstrated intraperitoneal free air, prompting an emergency operation. Considering the perforations in the descending colon, we performed Hartmann's operation. However, in addition to the histopathological results, bloody stools persisted postoperatively; thus, enteritis caused by CMV infection was suspected. Furthermore, CMV pp65 antigen-positive blood cells were detected, leading to the diagnosis of CMV colitis. Consequently, ganciclovir was administered, and persistent bloody stools resolved. DISCUSSION: CMV infection occurs asymptomatically during childhood and then remains latent in the body over time. Although CMV colitis is common in patients undergoing chemotherapy for hematologic malignancies, it is rare in mCRC cases. However, immunocompromised patients receiving long-term steroid therapy for chemotherapy are at a high risk of CMV reactivation. Therefore, CMV colitis should be considered one of the differential diagnoses based on persistent diarrhea and bloody stools, as well as ulcer formation observed on colonoscopy. CONCLUSION: Although CMV enteritis during colorectal cancer chemotherapy is rare, CMV colitis should be suspected if patients experience prolonged diarrhea or bloody stools during chemotherapy. Therefore, early diagnosis by detecting CMV antigen-positive blood cells is important.