A diagnostic pitfall in iron-refractory microcytic hypochromic anemia with acquired ring sideroblasts initially treated as iron deficiency anemia-a case report.

Microcytic hypochromic anemia is commonly presumed to represent iron deficiency anemia (IDA) at initial presentation. However, failure to respond to iron supplementation and iron indices inconsistent with IDA should prompt early diagnostic reassessment. We report a 67-year-old woman with severe microcytic hypochromic anemia after ineffective iron therapy. Iron studies indicated iron loading with impaired iron utilization rather than iron deficiency. Bone marrow Perls staining revealed ring sideroblasts in 14% of erythroblasts. Further stratified evaluation supported an acquired ring sideroblast phenotype, but the etiology could not be conclusively established. The patient received multifactorial supportive management, including discontinuation of unnecessary iron supplementation, early transfusion support, erythropoietin during hospitalization, pyridoxine supplementation, infection treatment, and optimization of comorbidities. Hemoglobin gradually improved and remained stable during follow-up without further transfusion. This case underscores the importance of early reassessment in older patients with iron-refractory microcytic anemia and discordant iron indices. Bone marrow Perls staining is critical for identifying ring sideroblasts. Assessment including SF3B1 testing may aid etiologic stratification, but SF3B1 negativity alone is insufficient to exclude clonal myeloid disease.