Primary intracranial leiomyosarcoma in an immunocompetent patient: case report.

We report a case of intracranial leiomyosarcoma (LMS) arising after resection of neurofibroma at the cerebellopontine angle. A 45-year-old immunocompetent woman presented with recurrence of a tumor 9 years after resection performed in another hospital. Magnetic resonance imaging demonstrated a heterogeneously enhancing, dura-based mass at the left cerebellopontine angle. The tumor was subtotally removed via lateral suboccipital craniotomy. LMS was diagnosed based on histological and immunohistochemical findings. Postoperatively, although the patient was treated using local radiotherapy, she died due to rapid regrowth of the tumor. Reevaluation of the specimen obtained in the first operation led to a diagnosis of neurofibroma. Both LMS and neurofibroma rarely occur intracranially. LMS is generally thought to arise from smooth muscle cells of the blood vessels or pluripotent mesenchymal cells. In this case, LMS might also have originated from smooth muscle cells of the vessels in the neurofibroma, possibly associated with mechanical and/or heat stimulation during the previous surgery.