RESUMEN
A case with mantle cell lymphoma, blastic variant, involving the peripheral blood in a 78- year-old female was described. The circulating blast-like cells suggested the possibility of acute leukemia. The WBC count was 28.0x109/ L with the absolute lymphoctyosis, 14.0x109/L. The peripheral blood smears showed a medium to large-sized lymphocytes with blast- like chromatin and conspicuous nucleoli. Atypical cells showing cleaved or indented nucleus were frequently observed. By flow cytometric analysis, immunophenotype of the circulating leukemic cells expressed B-cell associated antigens (CD 19, CD20), coexpressed CD5, lacked CD23, and expressed monoclonal surface immunoglobulin. Bone marrow aspiration and bone core biopsy confirmed diffuse infiltration of lymphoma cells. Immunohistochemicalstain for cyclin D1 (PRAD1/Bcl-1) protein was strongly reactive in the nucleus and cytoplasm of the infiltrative lymphoma cells in the bone marrow. Cytogenetic analysis of the bone marrow aspirates showed the complex abnormalities. Heterotransplantations of the blastic mantle cell leukemic cells, 4x104/microliter, into the peritoneum of the severe combined immunodeficiency (SCID) mouse showed tumor formation and infiltration of malignant lymphoid cells into peritoneum, liver, bone marrow, diaphragm, spinal cord and testes. The histopathology, immunophenotype and cyclin D1 protein expression of xenotransplanted tumor showed identical findings that of the original peripheral blood.