Double-hit lymphoma is defined by a chromosomal breakpoint affecting the MYC/8q24 locus in combination with another recurrent breakpoint, mainly a t(14; 18)(q32;q21) involving BCL2. We present rare case of double-hit lymphoma with IgH/MYC and IgH/CCND1 fusions and summarize the previously reported cases with MYC and CCND1 breakpoint.Case study
A 79-year-old male with no known history of lymphoma presented with general fatigue. Imaging studies showed multiple lymphoadenopathy with bulky retroperitoneal lymph nodes. His peripheral blood and bone marrow aspiration smear revealed some medium abnormal lymphocytes. Flow cytometric studies of them revealed a CD5, CD19 and CD20 positive surface λ light chain restricted B-cell population. His lymph node biopsy specimen showed a diffuse infiltration of medium to large atypical lymphocytes. Immunophenotypic findings showed his neoplastic cells were positive for CD20, Cyclin D1, C-myc and weakly CD5. Ki-67 labeling index was 90%. So, his pathological diagnosis was mantle cell lymphoma, pleomorphic variant. Cytogenetic findings of lymph node showed complex karyotypes with multiple abnormalities including t(8;11;14)(q24;q13;q32). Fluorescence in situ hybridization analysis revealed four IgH/MYC and IgH/CCND1 fusion signals. He treated with eight cycles of rituximab–cyclophosphamide, doxorubicin, vincristine and prednisolone. Although his lymphoma was rapidly progressive, he died 1 year after initial diagnosis.Discussion
According to the summary of 326 cases with double-hit lymphoma that with MYC and CCND1 breakpoint was ∼10%. The great majority cases classified as aggressive variants of mantle cell lymphoma and had poor prognosis. Cytogenetic findings showed that MYC was cytogenetically joined to an IG locus in only 20% cases. Although this case was classified as mantle cell lymphoma, he was initially joined to an IG locus with IgH/MYC fusion. So, this case is interesting for thinking the timing and synergy of MYC translocation. We suggest that the activation of MYC might be an important progression pathway in this case.