Primary colonic lymphoma: clinical dilemmas in diagnosis and treatment strategy

Abstract Primary colonic lymphomas are uncommon, comprising ˂1% of colorectal cancers and up to 20% of gastrointestinal lymphomas. The most frequent subtype is diffuse large B-cell lymphoma (DLBCL), typically presenting with nonspecific symptoms such as abdominal pain or obstruction. Diagnosis requires histopathologic and immunophenotypic confirmation. While treatment is primarily systemic with immunochemotherapy, surgery may be necessary in cases of complications or for diagnosis. We report a case of a 75-year-old woman presenting with right-sided colonic obstruction. Imaging revealed a mass in the ascending colon; an extended right hemicolectomy with ileostomy was performed. Histopathology confirmed DLBCL with post-germinal center phenotype. The patient recovered uneventfully and was referred for outpatient oncology care. This case illustrates the diagnostic and therapeutic relevance of surgical intervention in selected presentations of primary colonic lymphoma.