What transformation can occur in chronic myeloid leukemia?

Chronic myeloid leukemia (CML) is characterized by the uncontrolled proliferation of myeloid cells, typically resulting from the presence of the Philadelphia chromosome, which involves a BCR-ABL fusion gene. Over time, if not effectively treated, CML can progress to a more aggressive phase referred to as "blast crisis," which is akin to acute phase leukemias.

In the context of CML, this transformation can occur into either acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL). The transition occurs due to the accumulation of additional genetic mutations during the chronic phase that lead to the loss of differentiation and maturation of the leukemic cells. As this blast crisis takes hold, the clinical picture shifts to one resembling acute leukemia, requiring different treatment approaches due to the increased aggressiveness and poor prognosis associated with this stage.

The other options do not accurately reflect the typical progression or complications associated with CML. While transformation to lymphoma or myeloproliferative disorders may contribute to other hematologic abnormalities or complications, they do not represent the key transformation seen in CML. Similarly, while chronic diseases can lead to anemia, it is not a transformation but rather a complication of the underlying disease process.