Objective: Schwannomas are benign tumors that originate from Schwann cells of the nerve sheath. Fine-needle aspiration cytology (FNAC) is a valuable tool for the pre-operative diagnosis of schwannomas, especially in locations where surgical resection is associated with significant morbidity. In this study, we aimed to identify the clinical, cytological, and immunohistochemical features of 17 schwannoma cases diagnosed by FNAC and to compare our findings with previously published case series in the literature.
Materials and
Methods: We retrospectively reviewed 17 cytological specimens from patients with a cytological diagnosis of schwannoma between 2019 and 2024. The clinical data of the patients were retrieved from the hospital information management system. The cases were re-evaluated based on their cytological features.

Results: Of these patients, 10 were female and 7 were male. The patients’ ages ranged from 36 to 78 years (mean 54 years). Four cases were hypercellular, seven showed moderate cellularity, and six were hypocellular. In all the cases, the cells formed cohesive fragments. All nuclei exhibited tapering ends and appeared wavy, hook-like, or comma-shaped. All cases displayed filamentous cytoplasmic extensions and syncytium-like clusters. Immunocytochemical evaluation was performed in all but two cases. S100 staining was strong in 14 cases and moderate in one. Sox10 was positive in five cases.

Conclusion: The diagnostic assessment of schwannomas integrates clinical evaluation, imaging, and cyto-histological analysis. FNAC facilitates preoperative planning by characterizing the lesion. Characteristic cytological findings include spindle cell clusters, nuclear palisading, Verocay bodies, and a fibrillary background.