Abstract
RATIONALE: The specific pathogenesis of the diffuse large B-cell lymphoma(DLBCL)is still indefinite and argumentative. It is known that DLBCL is the most common type of non-Hodgkin's lymphomas (NHL). A lot of cases of DLBCL such as primary gastric diffuse large B-cell lymphoma(PG-DLBCL) are reported. However, primary intestinal diffuse large B-cell lymphoma(PI-DLBCL) is unusual. PATIENT CONCERNS: We present a case of a 57-year-old male diagnosed in the Gastroenterology Department, which presented a bleeding duodenal ulcer with irregular borders. DIAGNOSES: The immunohistochemical staining showed: CD20(+++), CD10(+) and Ki-67>40%. INTERVENTIONS: The patient was successfully treated by Poly-chemotherapy with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vindesine and prednisolone). OUTCOMES: After 6 courses of chemotherapy treatment, the duodenal ulcer was completely healed by reviewing the UGIE. LESSONS: Our report might give further strength to avoiding the erroneous and missed diagnosis for PI-DLBCL which is different from common duodenal ulcer.