CD19-negative primary gastrointestinal tract lymphoma: A rare case report

Among all non-Hodgkin lymphomas, diffuse large B-cell lymphoma (DLBCL) is the most prevalent subtype, comprising roughly 25–30% of adult cases. DLBCL usually expresses the pan-B-cell marker CD19, but rare CD19-negative variants have been known to occur. Compared to CD19-positive cases, these CD19-negative variants tend to display atypical immunophenotypes and have been linked to more aggressive disease progression and also with a less favorable prognosis. This issue is mainly pertinent in extra nodal DLBCL, where the disease arises outside lymph nodes. Furthermore, CD19 is an attractive therapeutic target and helps in personalized treatment, such as CAR-T cell therapy. Thus, CD19-negative variants pose a significant diagnostic and therapeutic dilemma.