Fine-needle aspiration of an adenoid cystic carcinoma of the larynx mimicking a thyroid mass

Adenoid cystic carcinoma (ACC) is most often primary in the major and minor salivary glands but can also arise from the submucosal seromucinous glands of the larynx and trachea. We report a case of adenoid cystic carcinoma of the larynx that presented as a diffuse swelling in the thyroid area. Fine-needle aspiration (FNA) was consistent with a neoplastic process, which was difficult to classify further but was felt to be of thyroid origin. Subsequent gross and histopathologic examination showed the lesion to represent an ACC arising from the larynx. This case highlights the need to be aware of unusual lesions that may arise in the region of the thyroid. Knowledge of these non-thyroidal lesions that can clinically mimic a thyroid mass will help in making the correct cytologic diagnosis when these lesions are sampled by FNA.