An unusual case of smoldering AML with prolonged indolent clinical course and spontaneous remission in the terminal phase.

An unusual case of acute myeloblastic leukemia (AML) with indolent clinical course and spontaneous remission in the terminal phase is described. A 63-year-old male has been diagnosed to suffer from AML, subtype M2. Chromosomal analysis showed 46,XY,del(6)(q21). Clinical course was slowly progressive ("smoldering" AML). The patient did not require cytoreductive drugs, and occasional supportive therapy was his only treatment. Five years from diagnosis patient exhibited spontaneous remission of the disease, accompanied with disappearance of del(6q) clone. Six months after, relapse occured and patient died from CNS bleeding. Additional curiosity in this case is the fact that patient's older brother died of acute lymphoblastic leukemia at the age of 71 years. Possible mechanisms of spontaneous remission of AML and genetic predisposition for human leukemia are discussed with a review of the literature.