Type 1 neurofibromatosis and adult extremity sarcoma. A report of two cases.

We report two cases of malignant soft-tissue tumours--one myxoid malignant fibrous histiocytoma and one pleomorphic rhabdomyosarcoma--which were diagnosed in two young adult patients with type 1 neurofibromatosis (NF 1). The patients were evaluated with criteria for Neurofibromatosis 1 and NF 1 gene analysis was performed. Four of seven criteria were found in both patients. The tumours were stage II and III respectively. Both patients were treated with radiotherapy or chemotherapy and surgical intervention. Diagnoses of myxoid malignant fibrous histiocytoma and pleomorphic rhabdomyosarcoma in adult NF 1 patients are exceedingly rare. Thus detection of subtypes of rhabdomyosarcoma and malignant fibrous histiocytoma with immunohistochemistry may be helpful for the management of these tumours among other pleomorphic sarcomas that may occur in type 1 Neurofibromatosis.