To the Editor: An 88-year-old man presented to Gastroenterology Clinic with a 4-month history of abdominal pain and diarrhea, passing watery stools up to 10 times per day. He denied weight loss or rectal bleeding. He had a history of previous bladder cancer, ischemic heart disease, and atrial fibrillation. He was still very fit and active, living independently. Physical examination was unrevealing without organomegally or palpable lymphadenopathy.
The complete blood count, differential and chemistry studies including liver function tests were within normal limits. His albumin was low 28 g/l (32–46) and lactate dehydrogenase raised 200 IU/l (120–150). He was negative for the human immunodeficiency virus.
At colonoscopy, the entire length of colonic mucosa was studded with nodules up to 12 mm in diameter (Figure 1a). These appeared to be vascular and some had a white-capped appearance consistent with inflammation. The ileo-caecal valve was grossly distorted, appearing bulbous and nodular (Figure 1b). The terminal ileum was only able to be intubated a short distance due to narrowing but also contained nodules (Figure 1c). A gastroscopy was completed, which demonstrated a normal stomach but similarly nodular and ulcerated mucosa in the examined duodenum (Figure 1d). Histology from biopsies demonstrated expansion of the lamina propria with atypical lymphoid cells. The cells were a monotonous, diffuse population with hyperchromatic irregular nuclei. There were only a small number of plasma cells within this lymphoid proliferation. A panel of immunoperoxidase stains showed a strong diffuse positive stain for CD20, CD21, CD45, and BCL-2, while were negative for CD3, CD5, CD10, CD23, and cyclin D1. This was felt to be most consistent with marginal zone lymphoma. He was negative for Helicobacter pylori infection.
A full body computed tomography (CT) scan was obtained. This revealed multiple areas of enhancing nodules scattered throughout the colon. In addition, there was extensive mesenteric lymph nodes and smaller nodes in the mediastinum and lower neck.
In view of the above findings and the patients’ status and preference, he was commenced on single-agent chlorambucil. At cycle 4 of a planned 6 months of treatment, his weight had stabilized and diarrhea had resolved. A follow-up CT scan demonstrated significant reduction in the size of the colonic lesions and abdominal lymphadenopathy, with no new sites of disease.
Primary colorectal lymphoma is rare, involved in only 0.2–0.6% of large bowel malignancies (1). Marginal zone lymphomas originating from mucosa-associated lymphoid tissue (MALT) comprises 8% of all non-Hodgkin lymphomas. They may arise from a wide range of extranodal sites, most often the stomach (70%). The small intestine is thought to be involved <1% of the time (2). No reports exist of whole-bowel involvement with marginal zone lymphoma. One case report exists of lymphoma affecting the whole gastrointestinal tract in a patient with mantle cell lymphoma (3).
Macroscopic appearances of colorectal lymphoma at colonoscopy may differ. They may be broadly characterized into mucosal type, polypoid type, and massive type (4). Further subtyping may be possible into erosive or ulcerative. Our patient had features that crossed over many of these classifications.
Evidence for management for primary colorectal lymphoma is restricted due to the small number of patients with various histological subtypes and different stages at presentation. For more localized disease, surgical resection may be an option, however chemotherapy remains the basis of treatment as they almost always extend beyond local fields (5).
Informed consent was obtained from the patient for the publication of their information and imaging.