Richter’s Syndrome in a Dog

Abstract

An 11-year-1-month old spayed Shih Tzu was diagnosed as suffering from B-cell chronic lymphocytic leukemia (B-CLL) by bone marrow aspiration biopsy and molecular analysis of the bone marrow using polymerase chain reaction (PCR). The disease went into clinical remission in response to chemotherapy with melphalan and prednisolone, and the medication was stopped on the 117 th day. The dog returned to our clinic because of lymphadenopathy and wheezing on the 382 nd day at the age of 12years and 1 month. Fine needle aspiration biopsy of the superficial lymph nodes showed increase of lymphoblasts, and the molecular analysis of them revealed a cloned arrangement of IgH genes. Based on these findings, the disease was this time diagnosed as B-cell high-grade malignant multicentric lymphoma, namely, Richter’s syndrome, which occasionally occurs as a development of CLL. The base sequence of PCR products obtained at the onset of the CLL was different from that of PCR products from the lymphoma one year later.