Giant cell-rich extrapleural solitary fibrous tumor: Cytological findings and differential diagnosis of a rare neoplasm.

Extrapleural solitary fibrous tumor (ESFT) is a rare neoplasm with a variable biological behavior that may occur almost everywhere in the body, as it has been reported in head and neck, back, retroperitoneum, inguinal region and more. The diagnosis of ESFT may be challenging, especially in case of its morphological rare variants such as giant cell-rich ESFT. Fine-needle aspiration cytology (FNAC) is a rapid, poorly invasive, safe diagnostic technique, which is recently proving useful for the preoperative diagnosis of mesenchymal neoplasms. Herein we report a case of a FNAC diagnosis of giant cell-rich ESFT, focusing on its morphological and immunocytochemical characteristics, and showing how cytology may be an effective tool in the preoperative diagnosis of mesenchymal neoplasms, allowing the correct surgical management of the patient.