Malignant bone tumors associated with neurofibromatosis.

Neurofibromatosis (von Recklinghausen's disease), a phakomatosis inherited as an autosomal-dominant trait, predisposes to multiorgan neoplasia as well as to skeletal abnormalities. In an attempt to define more clearly the nature of osseous malignant lesions associated with von Recklinghausen's disease, we reviewed three cases of coexistent neurofibromatosis and malignant tumors of bone. None of the tumors was considered neurogenic. One patient had a fibrosarcoma, and two patients had malignant fibrous histiocytomas. No gross relationship to nerves was demonstrated, and special studies for axons were negative. Primary neurogenic sarcomas of bone are extremely rare; the diagnosis should be considered only when the tumor originates from an intraosseous nerve or contiguous neurofibroma. The occurrence of primary bone sarcomas in patients with neurofibromatosis seems to be a sporadic event.