Ileocecal CD5-Positive Diffuse Large B-Cell Lymphoma Presenting with Acute Obstructive Symptoms: A Case Report

Primary gastrointestinal lymphoma is a rare form of extranodal non-Hodgkin lymphoma, accounting for approximately 1%-4% of all gastrointestinal malignancies. Among primary gastrointestinal lymphomas, involvement of the small intestine accounts for approximately 20%-30% of cases. CD5-positive diffuse large B-cell lymphoma (DLBCL) is a rare variant, representing approximately 5%-10% of all DLBCL cases and is associated with advanced age, extranodal involvement, and poorer prognosis. We report a rare case of ileocecal CD5-positive DLBCL presenting with acute obstructive symptoms.

An 80-year-old man presented with abdominal pain and fever. Contrast-enhanced CT demonstrated circumferential wall thickening in the ileocecal region with enlarged regional lymph nodes, resulting in marked luminal narrowing and raising suspicion for locally advanced right-sided colon cancer presenting with acute obstructive symptoms. Emergency laparoscopic right hemicolectomy was performed. Intraoperatively, the tumor appeared hard and showed dense adhesion to the duodenum, with suspected duodenal involvement. The gross specimen revealed an 8 × 7 × 4-cm ulcerated mass arising from the terminal ileum. Histopathology confirmed CD5-positive DLBCL (non-germinal center B-cell type), and regional lymph nodes were histologically negative (0/11). The postoperative course was uneventful, and the patient was referred to the hematology department. PET-CT was initially recommended but deferred by the patient; later imaging suggested disseminated disease, and rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone immunochemotherapy was initiated, although the long-term outcome could not be confirmed.

Malignant lymphoma should be considered in the differential diagnosis of acute obstructive symptoms, even when imaging findings suggest carcinoma. Prompt surgical intervention can facilitate definitive diagnosis and timely referral for systemic therapy in selected cases.