Rationale: Second diffuse large B-cell lymphoma (DLBCL) after treatment of acute lymphoblastic leukemia (ALL) is uncommon. To our knowledge, primary middle ear DLBCL which presents CD20-negative and coexpression of MYC and BCL-2 has not been reported yet. Patient concerns: A 20-year-old Chinese man complained fever and weakness for 2 months. Subsequently bone marrow morphology and flow cytometry immunophenotype suggested ALL. Administrated with 9 cycles of multiagent combined chemotherapy, he felt right ear progressive hearing loss, otalgia, aural fullness. Otoendoscopic examination revealed a pitchy mass obstructing the right external auditory canal. Then the mass resection was performed for biopsy and immunohistochemistry examination. Diagnosis: The mass was diagnosed as DLBCL which was negative for CD20 and double expression of MYC and BCL-2. Interventions: Chemotherapy. Outcomes: The patient eventually gave up and died of severe infection. Lessons: Although intensive chemotherapy has markedly improved the survival of ALL, more and more secondary cancers have been reported, In addition, primary middle ear lymphoma is much rare; hence, it is easy to be misdiagnosed. Furthermore, DLBCL with negative CD20 and double expression of MYC and BCL-2 is aggressive, which is characterized by chemotherapy resistance and inferior survival rates. We discuss this case aiming at raising awareness of tumors secondary to ALL and exploring the appropriate treatment options for the rare DLBCL.