Hybrid neurofibroma-schwannoma of the ankle: A case report.

Peripheral nerve sheath tumors include a range of well-defined pathologic entities from benign tumors such as schwannoma and neurofibromas to high-grade malignant neoplasms such as malignant peripheral nerve sheath tumors (MPNST). Hybrid neurofibromas-schwannomas have recently been described in the literature as nerve sheath tumors with schwannoma-like nodules within a neurofibroma-like tumor. We present a case of a 72-year-old female who initially presented with a non-painful soft tissue mass to the right ankle. Magnetic resonance imaging (MRI) was obtained which revealed a peripheral nerve sheath tumor located adjacent to the posterior tibial nerve. Due to her concerns of malignancy, the patient underwent surgical excision of the peripheral nerve tumor. The pathology report revealed a large peripheral nerve sheath tumor, consistent with hybrid neurofibroma/schwannoma which was positive for biological markers SOX-10, S100 and CD34, consistent with the diagnosis of a schwannoma-neurofibroma hybrid. [ABSTRACT FROM AUTHOR]