METHODS A 30-year-old patient was admitted for investigation of microcytotic, hypochromic anemia (hemoglobin 8.3 g/dl) with splenomegaly. METHODS Bone marrow smear showed a normocellular marrow with augmented severely dysplastic erythropoesis. Prussian-blue staining revealed an increased number of ring sideroblasts, thus myelodysplastic syndrome (refractory anemia with ringsideroblasts) was suspected. METHODS Review of former laboratory values and investigations of the patient's family revealed the correct diagnosis of x-linked sideroblastic anemia (XLSA). The patient was treated with oral pyridoxine. Hemoglobin levels steadily increased, so the diagnosis of pyridoxine-responsive sideroblastic anemia was made. Liver biopsy showed secondary fibrosis with beginning cirrhosis due to iron overload. Therapy with deferoxamine and phlebotomies was initiated. CONCLUSIONS XLSA is a rare differential diagnosis of acquired forms of sideroblastic anemias. A high degree of clinical suspicion is necessary for diagnosis because morphological studies such as histology and cytology may not yield conclusive results. A correct diagnosis is especially important because of the uncomplicated therapeutic options.