Pleural-based neuroblastoma-like schwannoma: a case report with cytologic findings and review of literature.

We report a rare case of a 45-year-old African American woman with Neuroblastoma-like Schwannoma (Neurilemmoma) occurring in the posterior mediastinum as a pleural-based mass noted on computed tomography (CT) scan. A CT-guided core biopsy of the mass was performed and core biopsy imprints were prepared during the procedure. A Diff-Quik stain was performed for on-site evaluation of specimen adequacy. The hematoxylin and eosin (H&E) staining was evaluated subsequently. Immunohistochemistry panels were applied to the same specimen. The cytologic findings of the core biopsy imprints showed hypercellular smears with a predominance of small cells with atypical features including hyperchromatic, round nuclei and occasional nucleoli. Neurocytic rosettes were particularly appreciated on H&E stain. The immunohistochemical results exhibited strong and diffuse immunoreactivity for S-100 and vimentin. This case enriches the cytopathology literature by providing awareness of this tumor presenting as a posterior mediastinal mass.