Malignant fibrous histiocytoma of bone associated with type-1 neurofibromatosis. A case report.

V on Recklinghausen disease, or neurofibromatosis, is a congenital and familial disorder with an autosomal dominant pattern of inheritance. The disease primarily affects ectodermal tissues arising from the neural crest. It is divided into two basic forms: peripheral (type 1) and central (type 2), characterized by distinct skeletal and soft-tissue manifestations1-6. Type-1 neurofibromatosis usually manifests in early childhood and is more frequent than the type-2 form of the disease7,8. Skeletal abnormalities and dysplasias, including erosive or pressure bone defects, pseudarthroses, and cranial defects, are diagnosed in approximately 80% of patients with type-1 neurofibromatosis. In addition, multiple nonossifying fibromas that predominantly affect the metaphyseal parts of the long tubular bones tend to develop in patients with this type of the disease1. The most serious, and often fatal, complication of the disease is a malignant peripheral nerve sheath tumor. Most cases are located within the soft tissue of the proximal part of an extremity, the buttocks, or the shoulder girdle. Skeletal involvement usually occurs as a result of secondary invasion by a soft-tissue lesion; a primary malignant peripheral nerve sheath tumor in bone is extremely rare9-12. These malignant tumors are highly aggressive, with a high propensity for distant metastases, especially to the lung, liver, and bones11-13. We are aware of only one reported case of irradiation-induced malignant transformation of a neurofibromatous bone lesion of von Recklinghausen disease to malignant fibrous histiocytoma14. We describe the case of a young patient with type-1 neurofibromatosis in whom a malignant fibrous histiocytoma of bone was diagnosed at the site of fibrous bone lesions without previous irradiation. The patient was informed that data concerning the case would be submitted for publication. A thirty-eight-year-old man with von Recklinghausen …