SECONDARY CHRONIC MYELOGENOUS LEUKEMIA - A DIVERSE PATHOGENESIS

A patient with myasthenia gravis and a thymoma did not respond to thym ectomy. He was submitted to radiotherapy concurrent with steroid thera py followed by an alkylating based chemotherapy Four years later, he d eveloped an otherwise typical Philadelphia chromosome/BCR-ABL positive chronic myelogenous leukemia (CML) that quickly evolved to a blast cr isis. We discuss the possible cause-effect mechanism between the previ ous treatment and CML, and suggest that a distinct mechanism, albeit u nknown, could be involved in the development and progression of second ary CML.