67 year old female with a history of breast cancer diagnosed 2 years prior to this biopsy and treated with cytotoxic chemotherapy.
Therapy related myeloid neoplasms include therapy-related acute myeloid leukemia (t-AML), myelodysplastic syndrome (t-MDS), and myelodysplastic/myeloproliferative neoplasms (t-MDS/MPN). These neoplasms occur as late complications of cytotoxic chemotherapy and/or radiation therapy administered for a prior neoplastic or non-neoplastic disorder.
Cytogenetic analysis of the bone marrow specimen in this case was abnormal showing a t(6;11)(q27;q23) by karyotype and a MLL gene rearrangment in 90.5% of cells examined by FISH.
A balanced chromosomal translocation is seen in about 25% of cases of therapy-related myeloid neoplasm. Such cases are generally associated with a short latency period, most often present as overt AML without a preceding myelodysplastic phase, and are associated with prior topoisomerase II inhibitor therapy.