Metastatic epithelioid sarcoma to the brain: palisaded necrosis mimicking glioblastoma multiforme.

Epithelioid sarcomas are rare, morphologically distinct tumors that have a propensity to arise in the extremities. Brain metastasis from epithelioid sarcoma are a relatively rare occurrence. We report a case of brain metastasis in a 50-year-old man who was previously diagnosed with an epithelioid sarcoma arising in the elbow. Before the diagnosis of brain metastasis, he had developed an axillary lymph node metastasis. He presented with neurologic symptoms of progressively worsening headache and loss of vision on the right side. He underwent gross total resection of an occipital lobe mass. Histologically, the tumor was focally characterized by prominent perinecrotic pseudopalisading and demonstrated immunoreactivity with antibodies to cytokeratin AE1/3 and CAM5.2; the tumor did not stain with glial fibrillary acidic protein antibody. The literature is reviewed and the morphologic distinction between metastatic epithelioid sarcoma and other central nervous system neoplasms is discussed.