Transformation of myeloma into Ph1-negative CML with plasma cell antigens

We report a patient in whom Ph1-negative chronic myelogenous leukemia (CML) developed 15 years after the diagnosis of myeloma. Combined staining of morphologically myeloid elements in the peripheral blood for myeloid and plasmacytoid antigens revealed double-marker expression, suggesting that the two neoplasms arose from a common originator cell.