Chronic lymphocytic leukemia/small lymphocytic lymphoma with t (2;18) (p12;q21) accompanied by a cutaneous nodule with histological features of diffuse large B-cell lymphoma.

ABSTRACT

A 73-year-old woman presented a 3-year history of indolent enlargement of cutaneous tumor nodules. Peripheral blood flow cytometry revealed thrombocytopenia (platelets; 85,000/µl) and the presence of an abnormal, small B lymphocyte population (CD5+, CD10-, CD20+, CD22+, CD23dim, FMC7+, SmIgλ+, and SmIgκ-; 4,000/µl). Skin biopsy indicated infiltration of CD5+, CD10-, CD20+, BCL2+, BCL6+, and cyclin D1- atypical large B-cells, suggesting diffuse large B-cell lymphoma. Cytogenetic analysis of the peripheral blood revealed a complex karyotype [t (2;18) (p12;q21) and +12]. Fluorescence in situ hybridization detected the presence of BCL2 split signal and the absence of IGH/CCND1 fusion signal. Cervical lymph node biopsy indicated a pseudofollicular pattern. The sequence of immunoglobulin heavy chain variable region from the peripheral blood and the skin tumor contained the same mutated pattern, and therefore, confirmed clonality. Because the patient's clinical course and skin tumor were indolent, the possibility of Richter syndrome was discarded, and the final diagnosis was chronic lymphocytic leukemia/small lymphocytic lymphoma, Rai stage IV and Binet stage C. The patient achieved complete remission after 4 cycles of a fludarabine plus rituximab regimen, without disease progression since >1 year of treatment.