Colon Lymphoma Mimicking Severe Ischemic Colitis

Abstract

Purpose: A 65-year-old male presented with weight loss, fever and night sweats. He reported mild diarrhea and left lower quadrant abdominal pain. The initial workup revealed left-sided colitis and multiple small ulcers on colonoscopy, and the biopsies showed nonspecific colitis. A repeat colonoscopy revealed similar findings. Two months later he presented to our institution with hematochezia and progressive anemia, with a hemoglobin of 7.7 mg/dl. Colonoscopy revealed a 3 x 4 cm ischemic-appearing sigmoid ulcer with a necrotic base (Figure 1, Panel A) at 25 cm from the anal verge. These findings, and lack of bleeding while obtaining biopsies, were suggestive of ischemic colitis. However, histopathology revealed lymphoepithelial lesions (Figure 2, Panel A), and a clonal population of cells was positive for CD10 and CD20 (Figure 2, Panel B), confirming large-B-cell non-Hodgkin's lymphoma. A PET scan demonstrated stage IV disease with bone and adrenal involvement. After 6 cycles of chemotherapy with rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP), his PET scan showed complete resolution of his disease. A colonoscopy done after 7 months showed a 5 mm area of stenosis at the 25 cm position, corresponding to the prior sigmoid ulcer. The ulceration was significantly reduced in size (Figure 1, Panel B). Balloon dilatation was performed at the stenosis site, and biopsies obtained during the procedure showed no evidence of malignancy. Diffuse large-B-cell lymphoma can occur anywhere in the GI tract. Patients tend to present with more systemic symptoms, a more advanced stage at diagnosis, and have a worse prognosis. Colonoscopy with biopsies is the principle diagnostic modality. The usual treatment is combination chemo-immunotherapy, and selected patients may be candidates for a trial of H pylori eradication. Considering lymphoma as a differential diagnosis in the workup of ischemic colitis with systemic symptoms may result in earlier recognition and a more favorable outcome.Figure 1: Sigmoid ulcer before (A) and after (B) chemotherapy. Figure 2: Histopathology showing lymphocytic infiltration (A) and positive immune staining for B lymphocytes (B).