Study of malignant peripheral nerve sheath tumor in cerebellopontine angle.

Malignant peripheral nerve sheath tumors (MPNSTs) are very rare soft tissue sarcomas, usually arising from somatic soft tissues or peripheral nerves. Primary MPNST of the cerebellopontine angle is extremely rare, with only a single case reported so far. Here, we report an unusual case of MPNST in cerebellopontine angle in a 25-year-old man presented with dizziness, left facial numbness, and tinnitus. After hospitalization, the tumor was treated with complete surgical excision followed by adjuvant chemotherapy and radiotherapy. Histologically, the tumor showed malignant spindle cells, which were with focal S-100 positivity on immunohistochemistry, and a diagnosis of the MPNST was made. This case is being reported for its rarity and presence in cerebellopontine and illustrated the difficulties in the diagnosis and treatment of MPNST, which to the best of our knowledge, has not been described before in the soft tissue sarcomas.