Aim A case of a 4-month-old girl who was admitted due to hepatosplenomegaly and diagnosed with osteopetrosis is presented here to remind pediatricians that osteopetrosis should also be considered in the differential diagnosis of anemia and hepatosplenomegaly.

Material and Method Case reports.

Results A 40-day-old girl patient was referred to us for examination and treatment due to the detection of hepatosplenomegaly in the external center. On physical examination, he was conscious and had a restless appearance. The anterior fontanel was 2*1 cm normal cambered, the sutures were open. Lymphadenopathy was not detected. The liver was palpated 4–5 cm below the jeans, the spleen was palpated 5–6 cm below the jeans. Traube was closed. On laboratory examination, hemoglobin was 4.7 g/Dl, platelet count was 22,000/mm3. Peripheral smear examination showed 80% lymphocytes,10% segmented,10% monocytes, a large number of monoblasts, single platelets. The reticulocyte count was 17%. Directly coombs was negative. Osmotic fragility and hemoglobin electrophoresis tests were normal. The patient underwent a bone marrow examination. Bone marrow aspiration examination showed significant dysplasia and erythroid, myeloid precursors in the bone marrow hypocellular, erythroid and myeloid series. Abdominal USG revealed no pathology other than hepatosplenomegaly. Although there was no infiltration on the chest X-ray, the bone structures had a sclerotic appearance. There was sclerosis in the calvarium in the direct radiographic examinations performed on it. On femoral radiographs, the appearance of bone within bone had begun to form. Lucent metaphyseal bands were present in the distal metaphysis of both femurs. Bone marrow transplantation was planned for the patient who was consulted to the pediatric hematology department. Methyl Prednisolone at a dose of 2 mg/kg/day was started upon deepening of bicytopenia during follow-up. The patient, whose general condition improved and bone marrow transplantation was planned, discharged.

Conclusions Osteopetrosis should also be considered in the differential diagnosis of infants with anemia, hepatosplenomegaly. The appearance of bone marrow elements in the peripheral blood smear is also an important clue in the diagnosis. Early diagnosis will contribute significantly to the reduction of morbidity and mortality.