RESUMO
The term malignant peripheral nerve sheath tumor (MPNST) refers to most spindle cell sarcomas arising from nerve or neurofibroma or showing nerve sheath differentiation and has been recently adopted by WHO. Malignant tumors of the peripheral nerve sheath are most commonly seen in association with the neurofibroma or at the site of irradiation and may also occur de novo. Its diagnosis has been called "one of the most difficult and elusive diagnosis in soft tissues diseases". We present a rare case of MPNST in a 12-year-old girl, who presented with a swelling of left cheek region of 2 months duration. Intraorally, the swelling extended buccally and palatally from premolar to tuberosity region. Swelling was fixed and firm to hard in consistency. A clinical diagnosis of odontogenic sarcoma was made. It was surgically excised and the histological features were suggestive of malignant peripheral nerve sheath tumor of the maxilla.