This report describes three unusual patients with lesions due to myeloblasts. In one instance, the patient presented with massive adenopathy. The second patient had bone lesions and a pathologic fracture. The third patient, with myelodysplasia, had diffuse skin lesions infiltrated with myeloblasts. These cases fit the diagnostic category of granulocytic sarcoma. Granulocytic sarcoma is a tumor of immature myeloid cells that may involve any site in the body but that most commonly affects the skin, soft tissues, lymph nodes, bone, and periosteum. Lesions can predate leukemia or occur late in an established chronic granulocytic leukemia or acute granulocytic leukemia. The most common presentation occurs late in the course of acute granulocytic leukemia or in chronic granulocytic leukemia as a herald to blastic transformation. Therapy for localized lesions is radiotherapy, which produces prompt shrinkage of the lesions but relapse occurs subsequently. Systemic chemotherapy also produces satisfactory clinical results. In all instances, therapy can only be considered palliative since virtually all patients have a short survival following the appearance of an extramedullary myeloblastic lesion. Recognition of this pathologic entity at an early stage may give us information on the best management for these patients.