ABSTRACT
Myeloid sarcoma is a rare presentation of acute leukemia as a solid tumor at various extramedullary sites. It may present concurrently, before or after the onset of systemic bone marrow leukemia. Unusual clinical localization may lead to misdiagnosis, or delayed diagnosis and treatment. We describe the first case, to our knowledge, of de novo myeloid sarcoma of the breast confirmed as acute promyelocytic leukemia. Immunohistochemical analysis, flow cytometry, fluorescent in situ hybridization analysis and molecular analysis using RQ-PCR of tissue samples should be routine in determining the correct diagnosis in this setting.
Subject(s)
Breast Neoplasms/diagnosis , Leukemia, Promyelocytic, Acute/diagnosis , Sarcoma, Myeloid/diagnosis , Adult , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Biopsy , Bone Marrow/pathology , Breast Neoplasms/genetics , Breast Neoplasms/metabolism , Diagnosis, Differential , Female , Flow Cytometry , Humans , Immunohistochemistry , In Situ Hybridization, Fluorescence , Leukemia, Promyelocytic, Acute/genetics , Leukemia, Promyelocytic, Acute/metabolism , Magnetic Resonance Imaging , Mammography , Sarcoma, Myeloid/genetics , Sarcoma, Myeloid/metabolism , Treatment OutcomeABSTRACT
The first event in origination of many childhood leukemias is likely the presence of preleukemic clone (transformed hematopoietic stem/progenitor cells with preleukemic gene fusions (PGF)) in newborn. Thus, the screening of umbilical cord blood (UCB) for PGF may be of high importance for developing strategies for childhood leukemia prevention and treatment. However, the data on incidence of PGF in UCB are contradictive. We have compared multiplex polymerase chain reaction (PCR) and real-time quantitative PCR (RT qPCR) in neonates from Slovak National Birth Cohort. According to multiplex PCR, all 135 screened samples were negative for the most frequent PGF of B-lineage acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). To explore the prevalence of prognostically important TEL-AML1, MLL-AF4 and BCR-ABL (p190), 200 UCB were screened using RT qPCR. The initial screening showed an unexpectedly high incidence of studied PGF. The validation of selected samples in two laboratories confirmed approximately » of UCB positive, resulting in â¼4% incidence of TEL-AML1, â¼6.25% incidence of BCR-ABL1 p190, and â¼0.75% frequency of MLL-AF4. In most cases, the PGF presented at very low level, about 1-5 copies per 105 cells. We hypothesize that low PGF numbers reflect their relatively late origin and are likely to be eliminated in further development while higher number of PGF reflects earlier origination and may represent higher risk for leukemia.