Primary diffuse large B-cell lymphoma of the cecum.

When found in the cecum or rectosigmoid junction, primary colorectal B-cell lymphoma is a rare malignant non-Hodgkin's lymphoma often associated with an unfavorable prognosis. Due to the nonspecific clinical symptoms, these uncommon tumors are often left undefined or misdiagnosed, resulting in delays in treatment and adverse patient outcomes. Contrast-enhanced computed tomography is the most commonly used medical imaging process for primary colorectal lymphoma, but due to the rarity of this disorder, accurate imaging diagnosis remains a clinical challenge. In this article, we report the case of a 70-year-old male who was diagnosed with primary B-cell lymphoma of the cecum. We focus on improving diagnosis through the utilization of radiological imaging modalities, particularly computed tomography (CT) and fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18-F-FDG PET/CT). While imaging modalities are important in recognizing colonic lymphomas, there are no pathognomonic imaging features for lymphoma; therefore, biopsy remains necessary for diagnostic confirmation.