Malignant Peripheral Nerve Sheath Tumor Presenting as Horner's Syndrome

Malignant peripheral nerve sheath tumor (MPNST) is a rare, aggressive sarcomatous tumor that arises from peripheral nerve sheath and shows Schwann cell differentiation. They are commonly seen among cases with existing benign plexiform neurofibromas, prior radiation treatment, and large germline mutations involving the entire neurofibromatosis 1 (NF1) gene. MPNST can have varied presentations; hence diagnosis remains a great challenge. Here we report a rare case of MPNST in an NF1 patient who presented with Horner´s syndrome. A young male reported swelling in the neck, dyspnea on exertion, and dysphagia. Subsequently, he was diagnosed to have a malignant peripheral nerve sheath tumor arising from the mediastinum and compressing the ipsilateral cervical sympathetic plexus causing Horner's syndrome. The patient underwent surgical resection of the mediastinal mass followed by chemotherapy. His symptoms improved significantly following treatment. This case report emphasizes the fact that high suspicion of MPNST is required when NF1 cases present with mass lesions, so that early surgical clearance with chemoradiation may offer a near-complete cure.