A Rare Case Report of the В-Cell Chronic Lymphocytic Leukemia Diagnosis During the Stage of Transformation into Diffuse Large B-cell Lymphoma (Richter Syndrome)

This paper reports a rare case of diagnosing В-cell chronic lymphocytic leukemia (CLL) during the stage of transformation into diffuse large B-cell lymphoma (Richter syndrome). A 62-year-old patient showed a local increase in the right upper jugular lymph node confirmed by PET/CT. By immunomorphological analysis of tumor tissue from the resected lymph node, diffuse large B-cell lymphoma (CD20+, CD23+, CD5+, BCL2+, BCL6+, LEF1+, Cyclin D1–, Ki-67 70 %) was diagnosed. At the same time, the peripheral blood test and myelogram revealed an increased absolute lymphocyte count and morphological heterogeneity of lymphocytes with predominating same-type small and medium-sized cells with rounded nuclei as well as abnormal larger cells with irregular-shaped nuclei and basophilic vacuolated cytoplasm. By flow cytometry, the immunophenotype of tumor В-lymphocytes corresponded to СD5-positive mature В-cell lymphoid tumor, mostly to В-CLL. According to the analysis of the bone marrow core biopsy sample, morphological pattern and immunophenotype of tumor cells (CD79+, CD5+/–, CD23+, LEF1+, Ki-67 5 %) were consistent with the diagnosis of В-cell small lymphocytic lymphoma/В-CLL. So, based on the total of obtained data, patient was diagnosed with small lymphocytic lymphoma/В-CLL transformation into diffuse large B-cell lymphoma (Richter syndrome) with a lesion in the right upper jugular lymph node.