A 63-year-old woman with newly diagnosed low-grade follicular lymphoma underwent a bone marrow biopsy for staging before treatment. Family history was unremarkable. She presented with borderline red cell index (red blood cells [RBCs], 3.49 × 10⁶/μL; hemoglobin, 11.7 g/dL) and normal white blood cells and platelets. Her physical examination showed no hepatosplenomegaly. Laboratory results revealed normal bilirubin and lactate dehydrogenase. Her bone marrow biopsy showed no evidence of lymphoma. Incidentally, the bone marrow aspirates revealed a prominent erythroid hyperplasia with striking dyserythropoietic abnormalities. Numerous erythroid precursors displayed megaloblastic changes, binucleated or multinucleated normoblasts (original magnification ×100; Wright stain). Few “gigantoblasts” with 5 to 8 nuclei were seen (inset). Occasional erythroid precursors with nuclear budding/irregularity were also detected. The abnormal precursors occupied 20% to 30% of the erythroid cells. Slightly increased storage iron was seen. Peripheral blood only showed RBC anisocytosis. Chromosomal analysis demonstrated a normal karyotype (46,XX).

The finding likely is congenital dyserythropoietic anemia (CDA) with characteristic clinical and morphologic features of CDA type III. It is well-known that CDA III can be familial (autosomal dominant) or sporadic (autosomal recessive). The genetic abnormality of the former has been recently identified as a KIF23 gene mutation on the locus of chromosome 15q23, encoding a mitotic protein essential for cytokinesis. Most patients with CDA III are asymptomatic and do not require treatment but genetic consulting is recommended.