Granular-cell tumor of trachea masquerading as Hurthle-cell neoplasm on fine-needle aspirate: a case report.

We report on a case of extraluminal tracheal granular-cell tumor which was interpreted as a Hurthle-cell neoplasm of the thyroid on fine-needle aspirate. Review of the literature reveals only one other such case. The patient was a 35-yr-old female who presented with an enlarged thyroid. Aspiration cytology revealed a syncytium of cells with abundant granular cytoplasm interpreted as a thyroid follicular neoplasm with Hurthle-cell change. However, histology of the resection specimen with immunohistochemistry confirmed it as a granular-cell tumor. The cytologic differential diagnosis of neoplasms with oncocytoid cytoplasm in and around the thyroid should include granular-cell tumor of the trachea.