A 12-year-old boy was hospitalized for a chronic compensated hemolytic anemia, with asthenia as the major complaint. No particular familial history was present and there was no exposure to toxic substances. Scleral icterus and mild splenomegaly were noted. Laboratory tests indicated Hb: 11.1 g/dL; mean cell volume: 90.2 fL; mean corpuscular hemoglobin concentration: 35.1 g/dL; red cell distribution width: 18.1%; reticulocytes: 121 3 10 9 /L. White blood cells and platelets were in reference range (RR). Haptoglobin was below the level of detection, lactic dehydrogenase: 310 UI/L (RR < 210), bilirubin: 35 lmol/L (RR < 18). Direct Coombs test was negative. Hemoglobin electrophoresis revealed HbA1: 96% and HbA2: 4%. No anomalies were detected in the erythrocyte activities of either glucose-6phosphate dehydrogenase or pyruvate kinase. Flow cytometric testing (CD55 and CD59 determination on erythrocytes and polymorphonuclears) for paroxysmal nocturnal hemoglobinuria was negative. May-Grunwald-Giemsa staining of the peripheral blood smear highlighted some peculiar erythrocyte shapes with numerous ''mushrooms'' (more than 2 per field at high power magnification) and some spherocytes among moderate aniso-poı ¨kilocytosis (mosaic figure; Image 1). A SDS-polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated decrease of protein band-3. Unfortunately, neither osmotic gradient ektacytometry nor molecular testing could be performed.
Mutations in the SLC-A1 gene encoding the band-3 protein are frequently reported as the cause of hereditary spherocytosis [1][2][3]. When numerous, ''mushroom'' but also ''puzzle'' ''fish''/''whale,'' or ''yeast''-shaped erythrocytes are associated with band-3 deficiency. Such bizarre erythrocytes can be also observed after bone marrow myelofibrosis and, occasionally, in non specific dyserythropoı ¨esis, but, in such contexts, mushroom cells are only scattered in the middle of a marked poı ¨kilocytosis.
Image 1. Mosaic image of bizarre erythrocytes (mushroom-/fish-/whale-shaped); May-Grunwald-Giemsa, 31000.