Two instances of neurofibrosarcoma arising in young siblings with neurofibromatosis are reported to add to the body of information concerning this potentially lethal complication of von Recklinghausen's disease. The optimum treatment to achieve control of the local disease, especially for centrally located tumors, has yet to be discovered. Results of recent data suggest that radical surgical resection combined with preoperative irradiation and chemotherapy may enhance local control of peripherally located sarcomas. This treatment modality may also obviate the need for amputation in those patients with soft tissue malignant conditions of the extremities. The efficacy of controlling systemic disease with adjuvant chemotherapy has not been demonstrated conclusively. Gallium 67 scanning may provide a method for the early detection of malignant degeneration in neurofibromas.