Erythroblastic islands in erythroleukemia.

Erythroblastic islands are distinct anatomical units allowing direct transfer of ferritin molecule into developing erythroblasts. A patient with Fanconi's anemia who developed acute erythroleukemia and hypotransferrinemia exhibited numerous erythroblastic islands in the bone marrow. This unusual finding in our patient is thought to be in response to an increased demand for iron caused by neoplastic erythropoietic proliferation in the absence of an adequate amount of transferrin.