Metastatic Gliosarcoma: Cytopathologic Characteristics with Histopathologic Correlations.

Gliosarcoma is a rare variant of glioblastoma multiforme characterized by a biphasic pattern of glial and mesenchymal differentiation. Fine-needle aspiration (FNA) is routinely employed to diagnose a number of primary and secondary malignancies in a variety of clinical settings. Herein, we describe the cytomorphologic features of a gliosarcoma metastatic to an extracranial location accompanied by corresponding clinico-radiologic and histopathologic findings in a 51-year-old man with a posterior mediastinal mass. The cytologic smears displayed a pleomorphic tumor comprised of spindled and epithelioid malignant cells. This case illustrates the ability of FNA to adequately diagnose a rare malignancy in the appropriate clinico-radiologic setting.