Cytopathology and Histopathology

Biography

Biography: Katherine Cochrane

Abstract

Myelodysplastic syndrome (MDS) comprises a heterogeneous group of clonal hematopoietic cell disorders characterized by cytopenias, morphologic abnormalities, ineffective hematopoiesis, and increased risk of transformation to acute leukemia.  Acute leukemia evolving from MDS is usually of myeloid lineage, while transformation into acute lymphoblastic leukemia (ALL) is extremely rare. We present the case of a 73-year-old Caucasian male who was found to have pancytopenia on routine blood work.  He continued to have progressive pancytopenia requiring intermittent transfusions.  Subsequent bone marrow biopsy revealed hypocellular bone marrow with dyserythropoiesis and increased blasts. A diagnosis of MDS with excess blasts (MDS-EB2) was rendered.  Three cycles of hypomethylating therapy were administered before treatment was discontinued due to severe cytopenias.  Repeat bone marrow biopsy showed normocellular marrow comprised of 50% moderate to large sized blasts with high nuclear to cytoplasmic ratios and prominent nucleoli.  Aberrant immunophenotype with expression of CD19 and TdT was consistent with B-cell ALL.  Retrospective review of the initial bone marrow biopsy revealed occasional blasts with lymphoid morphology, as well as variable expression of CD19.  These findings suggest a biphenotypic cell population at the time of initial MDS diagnosis with expansion of the clonal lymphoid population, while undergoing hypomethylating agent therapy.  Due to the patient’s poor performance status, he was unable to receive further treatment and died within a month of the second biopsy. The bilineage cell population supports the theory that MDS arises from a pluripotent precursor cell with chemotherapy regimen possibly responsible for alteration of the clonal evolution.