[An unusual way of manifesting acute granulocytic leukemia: granulocytic sarcoma of the breast. Apropos of a case with trisomy 22]

A case of granulocytic breast sarcoma in a 19 year-old-girl is reported. Surgical excision of the tumor was followed by radiotherapy of the breast and lymph nodes. Then 3 months later acute M2 myelocytic leukemia was diagnosed, complete remission being attained using rubidazone-cytarabine and maintained by monthly reinduction courses. Trisomy of chromosome 22 was present in leukemic cells and disappeared during remission. Its pathogenic significance is briefly discussed.