Primary T-cell Lymphoma of the Ileum with Difficulty of Diagnosis Due to Obstructive Colitis Caused by Transverse Colon Cancer

Abstract

A 50-year-old man received chemotherapy for transverse colon cancer with multiple unresectable liver metastases. The patient presented with fever and abdominal distension. CT showed colon and small intestinal dilation on the oral side from the cancer and a thickened terminal ileal wall. Bowel obstruction and obstructive enteritis due to transverse colon cancer were diagnosed preoperatively. Subtotal colectomy and resection of the thickened ileum were performed. Torn colonic taenia and histopathological findings of obstructive colitis were observed in the cecum. The thickened ileum had multiple ulcers, which were deemed to be ischemic changes similar to those in the cecum. Chemotherapy was continued postoperatively, but fever of unknown origin persisted, and thus, the ulcerative lesion of the ileum was reexamined. The ileal submucosa had medium to large atypical lymphocytes that were positive for CD3, CD4 and CD5 and negative for CD8, CD20 and CD56, confirming the diagnosis of primary ileal T-cell lymphoma. In this case, it was difficult to diagnose ileal malignant lymphoma because of obstructive colitis caused by transverse colon cancer. Double cancer of colorectal cancer and ileal malignant lymphoma is rare, but malignant lymphoma should always be considered in differential diagnosis for ileal ulcerative lesions.