2. Diagnostic Pathology Center, Shirakawa Kosei General Hospital, Shirakawa, Japan.
Pure erythroid leukemia (PEL) is characterized as a neoplastic erythroid hyperproliferation with maturation arrest, showing highly complex karyotypes, prominent clonal evolution, and a very aggressive clinical course. Here, we describe two cases of PEL that evolved from myelodysplastic syndrome (MDS), focusing on the immunophenotypic, cytogenetic, and molecular features of these cases. Case 1: A 77-yearold woman was diagnosed with PEL that evolved from MDS-refractory cytopenia with multilineage dysplasia. Her disease progressed rapidly despite 5 cycles of azacitidine treatment. The bone marrow (BM) aspirate revealed hypercellular marrow with 92.4% erythroid cells, which expressed CD7 and CD36. Case 2: A 43-year-old woman had MDS-refractory anemia for more than 15 years. When her disease progressed rapidly, the BM aspirate revealed hypercellular marrow with 95.4% erythroid cells, which expressed CD235a. There were several significant findings in our cases. First, flow cytometric analysis of BM cells showed different stages of erythroid maturation. Second, cytogenetics revealed extremely complex karyotypes. Finally, immunohistochemistry showed strong nuclear staining for p53 in BM erythroid cells. We suggest that increased p53 protein expression is correlated with complex karyotypes and worse outcomes, indicating PEL with a high degree of malignant behavior.
Keywords: Pure erythroid leukemia, myelodysplastic syndrome, complex karyotype, double minute chromosome, p53