Solid leukemic tumor. An uncommon presentation of a common disease.

Granulocytic sarcoma of the clavicle occurred in a 17-year-old boy. The patient had a densely sclerotic bony lesion with periosteal reaction and no peripheral blood manifestations of leukemia. Supraclavicular adenopathy developed after a preliminary diagnosis of Ewing's sarcoma was made, and a second biopsy was performed. Electron microscopy of the tissue showed Auer bodies and Charcot-Leyden granules characteristic of acute myelogenous leukemia. Combination chemotherapy, local irradiation, and clavicular resection have left the patient with no evidence of disease 50 months after diagnosis. Leukemia may appear as a solitary bone tumor before hematologic changes develop. Granulocytic sarcomas can have the radiographic and histologic appearance of primary bone tumors. Bone marrow examination and electron microscopy of biopsy tissue are diagnostic of leukemia and are important in all hospital investigations of round-cell tumors of bone.