Acute lymphoblastic leukemia secondary to myeloproliferative neoplasms or after lenalidomide exposure.

Philadelphia-negative (Ph) myeloproliferative neoplasms (MPN) do rarely transform to acute lymphoblastic leukemia (ALL). While causality is difficult to establish, a few cases of ALL arising after exposure to lenalidomide for registered indications (multiple myeloma, myelodysplastic syndrome with 5q deletion) have been described in the literature.