Early malignant change in a solitary neurofibroma not associated with neurofibromatosis: a case report

A 31-year old woman presented with a mass on the posterolateral aspect of the lower third of the right leg. The mass had undergone fine needle aspiration biopsy previously at another center and was diagnosed as neurofibroma. The patient was evaluated to determine the existence of neurofibromatosis but no positive findings were obtained, thus the mass appeared to be a solitary, local neurofibroma. The mass was totally excised with the involved nerve fascicles. The histopathological evaluation showed foci of malignant transformation of the solitary neurofibroma. The patient was reoperated on, and the surrounding tissues were widely excised together with the tibial nerve; the defect was grafted with the sural nerve. Clear margins were achieved. No complications ocurred and the patient was satisfied. She survived and had neither recurrence nor metastasis during 2 years follow-up. This patient is presented as a case report of a malignant peripheral nerve sheath tumor, specifically the focal malignant degeneration of a solitary neurofibroma.