A case of neurilemoma (schwannoma) that mimicked a pleomorphic adenoma (an example of potential pitfall in aspiration cytodiagnosis).

Needle-aspiration cytology of a case of benign neurilemoma (Schwannoma) from the neck is presented. It was clinically diagnosed as an enlarged lymph node, while on aspiration cytology, it was diagnosed as a pleomorphic adenoma. An excision biopsy, however, was diagnostic of neurilemoma. A review of cytologic material was undertaken, and it was felt that the cytologic features in Papanicolaou stained preparations in the aspirate were present that initially should have enabled the correct cytodiagnosis and distinction from a pleomorphic adenoma. The findings presented in this study were considered to be an example of a potential pitfall in the aspiration cytodiagnosis of a neurilemoma.