Background: Adenoid cystic carcinoma (ACC) of the larynx and trachea is very rare. Case: A 45-year-old man with ACC of the larynx presenting as a thyroid mass is reported in this study. Physical examination revealed a large solid thyroid nodule in the left lobe without any lymphadenopathy. A technetium thyroid scan showed multinodular goiter with cold nodules in the left lobe, isthmus, and functioning nodules in the right lobe. A large thyroid mass originating from the left side of the larynx, mostly the left vocal cord and the infraglottic part, was seen using enhanced magnetic resonance imaging after rupture of the thyroid cartilage on the left side. Ultrasound-guided fine needle aspiration smears and cell blocks of the thyroid nodule showed highly cellular smears composed of large tissue fragments, three-dimensional clusters, and sheets of neoplastic cells with slightly enlarged round and hyperchromatic nuclei. Immunohistochemical study showed that the cell block expressed C-kit and CK 7 on the cribriform growth pattern of the tumoral cells. However, protein expression of thyroglobulin and thyroid transcription factor-1 was not detectable. Conclusion: To approach a thyroid nodule, direct invasion or metastatic tumors of other organs must be borne in mind.