EP1051 - Primary Colonic Lymphoma: A Rare Presentation of Non-Hodgkin Lymphoma

Purpose/Background: Primary lymphoma of the colon is an uncommon malignancy, accounting for less than 10% of all gastrointestinal lymphomas and less than 1% of all colorectal malignancies. In this paper, we report a case of an elderly Filipino female who presented with intermittent nonspecific abdominal pain and occasional vomiting. Succeeding imaging showed a nodular circumferential mass in the cecum and proximal ascending colon including the ileocecal valve region with paracolic lymphadenopathy. The patient underwent robotic right hemicolectomy. Histopathologic specimen results showed round cell malignancy of the cecum. . Requested immunohistochemistry were done CD20, CD5, Cyclin D1 and Ki-67 all consistent with high-grade B-cell non-Hodgkin lymphoma.

Methods/Interventions: In this paper, we present the case of a 73-year-old female with a history of hypertension but no known family history of malignancy, who presented with intermittent, nonspecific abdominal pain. Colonoscopic evaluation revealed a friable, circumferential mass causing luminal narrowing at the ileocecal region. Biopsy specimens obtained during the procedure demonstrated predominantly necrotic material, raising the possibility of a superficial malignancy. Further imaging with contrast-enhanced computed tomography (CT) of the chest and abdomen demonstrated nodular circumferential wall thickening involving the cecum and ascending colon, including the ileocecal area. No pulmonary nodules or evidence of distant metastasis were identified.

Results/Outcomes: Given the patient's age, the indeterminate nature of the endoscopic biopsy, and the concerning imaging features suggestive of a malignant process, a robotic-assisted right hemicolectomy.

On final histopathology, a round cell malignancy of the cecum was considered. All surgical margins of resection were negative for tumor.

Additional stains were sent for confirmation, these include CD20, CD5, Cyclin D1 and Ki-67 all consistent with high-grade B-cell non-Hodgkin lymphoma.

Conclusion/Discussion: Primary colonic lymphoma is rare, comprising less than 1% of colorectal cancers, with the cecum being the most affected site due to its rich lymphoid tissue. Most cases are non-Hodgkin B-cell lymphomas, particularly diffuse large B-cell lymphoma (DLBCL). Symptoms are often nonspecific-abdominal pain, weight loss, bowel habit changes, or GI bleeding-making early diagnosis challenging. Some patients may present acutely with obstruction or perforation.

Diagnosis involves imaging and colonoscopy, but definitive confirmation requires histopathology and immunohistochemistry to identify B-cell markers like CD20 and CD79a. Accurate subtyping is essential, as some lymphomas mimic adenocarcinoma.

Treatment is primarily chemotherapy (e.g., R-CHOP for DLBCL). Surgery is reserved for complications or diagnostic uncertainty. Case reports highlight the variable clinical presentations and underline the importance of considering lymphoma in atypical cecal lesions for timely and effective management.

CT scan findings
Nodular circumferential bowel wall thickening in the cecum and proximal ascending colon including the ileocecal region spanning 6.4cm with a maximum thickness of 2.6cm exhibiting arterial enhancement with a mildly hypodense rim. Surrounding fat stranding densities and round prominent enhancing pericolic lymph nodes.
Gross specimen
Specimen resected consists of ileum, cecum, ascending, and proximal transverse colon. Noted on the cecum is a cream-tan nodular area which measure 7.0 x 6.8cm in greatest dimension. The mass grossly invades up to the serosa. Twenty-seven pericolic lymph nodes harvested. All surgical margins of resection were negative for tumor.