Osteolytic lesions rarely occur in acute myeloid leukemia (AML). We reported an atypical form of the disease, with marrow fibrosis and osteolytic lesions, in a 17-year-old patient, whose main symptom was lumbar pain. Diagnosis of AML was established by bone marrow and lymph node histological analysis. Computed tomography (CT) scan and 99mTc-MDP bone scintyscan revealed osteolytic lesions. After remission-induction, bone marrow aspirate and biopsy showed no evidence of leukemic infiltration, nevertheless bone abnormalities persisted on 99mTc-MDP bone scintyscan, suggesting residual disease. Suspect bone areas were irradiated with symptomatic improvement and 99mTc-MDP bone scintyscan showed the appearance of more condensed bone compared with the pre-radiotherapy pattern. Twelve months later he was readmitted to the hospital due to relapse of AML and died of sepsis within a few weeks. This report illustrates the usefulness of histological studies to establish diagnosis of AML in atypical cases, as well as the importance of CT scan and bone scintigraphy scan for the identification of osteolytic lesions. It also provides additional data as evidence that although osteolytic lesions indicate an adverse prognosis in AML, local irradiation results symptomatic relief.