Epithelioid malignant peripheral nerve sheath tumor involving maxillary sinus.

We present a case of epithelioid malignant peripheral nerve sheath tumor (MPNST) located in the maxillary sinus region in a young man. The clinical history was short, but at admission the neoplastic infiltration was so extensive that only diagnostic biopsy was performed. The patient received palliative treatment and died 6 months later. Histologically, the neoplasm had a predominant epithelioid component. Neoplastic tissue was vimentin, S-100, Cam 5.2 and neuron-specific enolase positive. P53 protein reaction was found in 6% of the cells and the proliferation index assessed with Ki-67 was 52%. An appropriate immunohistochemical panel was essential for the final diagnosis of this epithelioid malignant tumor, with the location rather unusual for MPNST.