A 70-year-old woman presented with fatigue and splenomegaly. She had an 8-year history of polycythemia vera and had been diagnosed with secondary hemolytic anemia 2 years previously. Molecular analysis demonstrated a JAK2 V617F mutation. Laboratory testing revealed the following: hemoglobin, 37 g/L; reticulocyte, 16.56%; white blood cell count, 44.05 × 10⁹/L; platelet, 565 × 10⁹/L; and evidence of hemolysis (indirect bilirubin, 109.1 μmol/L; lactate dehydrogenase, 2362 U/L; immunoglobulin G⁺ by Coombs test). Serum iron and ferritin were increased. CD55 and CD59 expressions were normal. Secondary hemolytic anemia was diagnosed. Wright-Giemsa staining of peripheral blood smears (panels A-C, original magnification ×1000) demonstrated numerous nucleated red blood cells (54/100 white blood cells) with 27% ring sideroblasts (red arrow). Numerous inclusions (Pappenheimer bodies, blue arrow) were also present in the erythrocytes. Prussian blue staining confirmed the inclusions were iron positive (panels D-F, original magnification ×1000). Gene sequencing revealed wild-type SF3B1. The patient received a blood transfusion and was treated with dexamethasone and immune globulin. One week later, her hemoglobin level had increased to 107 g/L and ring sideroblasts were absent in the blood smear.

This case is a rare example of the transient presence of numerous ring sideroblasts and Pappenheimer bodies in the peripheral blood in the acute phase of hemolytic anemia secondary to polycythemia vera.