Lymph node blast crisis of chronic myelogenous leukemia. One case report.

We present a patient with philadelphia chromosome (ph')-positive CML with extramedullary blast crisis in the lymph nodes before the bone marrow blast crisis. The morphological and cytochemical studies of lymph node touch preparation, and cytogenetic studies of lymph node tissue confirmed the extramedullary lymphoid blast transformation of CML, while the bone marrow continued to show the chronic phase of CML. When we changed our treatment to use Vincristine-Prednisolone therapy, the lymphadenopathy disappeared gradually. This case shows that the clinical and prognostic features of extramedullary disease can strongly affect disease acceleration in CML, and the therapy should be changed promptly. Besides, cytogenetic study of extramedullary tumor tissue in CML can be useful for accurate diagnosis.