Myeloproliferative syndromes: a unique presentation of chronic myelogenous leukemia (CML) as a primary tumor of bone.

A 45-yr-old female presented with a rapidly enlarging bony tumor that was eventually identified as a Philadelphia chromosome (Ph1)-positive myeloproliferative disorder with extramedullary blastic transformation. This transformation occurred in the absence of demonstrable chronic or acute leukemic phase. She had no history of a chronic or prodromal illness in spite of a bone marrow biopsy showing myelofibrosis and liver biopsy documenting extramedullary hematopoiesis. This case represents a unique constellation of features of the myeloproliferative syndrome in which the diagnosis was obscure until special stains of the bony tumor and cytogenetic studies were performed.