Metastatic Alveolar Soft Part Sarcoma Presenting as a Dural-based Cerebral Mass

Abstract

Sarcoma metastatic to the brain is uncommon and rarely occurs as the initial manifestation of tumor. Alveolar soft-part sarcoma, a rare but well studied subtype of a soft tissue sarcoma with a propensity for central nervous system invasion, presenting with brain metastases, has been reported only once previously. We report the case of a 28-year-old man who presented with partial seizures and who was found to have a homogeneously enhancing frontal lesion on a broad dural base disclosed by computed tomography. preoperatively, the lesion was thought to be a meningioma. The tumor was excised easily and had features typical of an alveolar soft-part sarcoma, which were revealed by light and electron microscopy as well as immunohistochemical analysis. Multiple lung nodules compatible with metastases were found on a chest film. Meningeal dissemination has been reported in a variety of sarcoma types, including rhabdomyosarcoma, fibrosarcoma, and leiomyosarcoma. We add alveolar soft-part sarcoma to this list and suggest that increased recognition of the propensity for these tumors to exhibit metastatic spread to the dura should eliminate diagnostic confusion and provide an earlier diagnosis of these rare lesions. The patterns of spread in metastatic sarcoma deserve further study.