Breast solitary schwannoma: fine-needle aspiration biopsy and immunocytochemical analysis.

A case of intramammary solitary schwannoma (SS) (benign neurilemoma) diagnosed by fine-needle aspiration biopsy (FNAB) and supported by immunocytochemical study is reported. The tumor arose in the right breast of an 18-yr-old woman and was clinically and radiologically considered a fibroadenoma. The smears obtained by FNAB of the lump showed clusters of spindle-shaped cells and suggested a benign mesenchymal neoplasm. The presence of some structures reminiscent of Verocay bodies and the immunocytochemical reactivity for S-100 protein antiserum demonstrated the schwannian nature of the tumor and suggested the diagnosis of SS. The final histologic examination confirmed the cytologic diagnosis.