Expansion of trisomy 8 and Sweet syndrome in a prolonged course of aplastic anemia.

We describe a 17-year-old boy with aplastic anemia who had Sweet syndrome develop with increasing expansion of trisomy 8. The diagnosis of aplastic anemia was made at 6 years of age. Cytopenias partially responded to danazol therapy. Cytogenetic studies of bone marrow (BM) cells were normal until the detection of trisomy 8 at 14 years of age. This clone increased with the progression of cytopenias. Cell sorting and fluorescence in situ hybridization analysis revealed that trisomy 8 was present only in nonlymphoid elements. When the patient was 17 years of age, Sweet syndrome developed. BM study showed myelodysplastic features, in which trisomy 8 occupied 74% of BM cells with additional chromosomal changes. Trisomy 8 may contribute to the late transformation of myeloid lineages in BM failure.