An 11-year-old white girl was admitted to The Children's Hospital of Philadelphia in July 1983 for evaluation of metastatic tumor. She had been well until July 1982, when a mass developed over the right scapula. Treatment with warm compresses and antibiotics resulted in no improvement, and incision and drainage were unproductive. A biopsy at another hospital was interpreted as showing a primitive neuroectodermal tumor. There was no evidence of metastatic disease. She then underwent excision of the tumor with the underlying scapula. No further treatment was administered. She remained well until February 1983, when she began to complain of occasional lower back and thigh pains. Her symptoms worsened over the succeeding 3 months, despite treatment with analgesics and physical therapy. By May 1983, she was no longer able to attend school because of weakness and pain, and had sustained a 10% weight loss during the previous 2 months. She was admitted to her original hospital, where bone scan and bone marrow biopsy showed disseminated tumor; she then came to The Children's Hospital of Philadelphia. On examination, she appeared acutely and chronically ill. It was very uncomfortable for her to move, and she walked with a slow, stooped, shuffling gait. She complained of tenderness in the lower back and both sides. There were no other abnormalities on examination. The hemoglobin level was 9.7 gm/dl, following transfusion at the other hospital; white blood cell count was 6,900/mm3 with a normal differential, and the platelet count was 480,000/mm3. A 24-hr urine test for VMA excretion was normal. She underwent bone marrow aspiration and biopsy, and the radiographs and pathology slides from the other hospital were reviewed.