Thyroid metastasis from adenoid cystic carcinoma of the lung: a case report and literature review

Both adenoid cystic carcinoma (ACC) and thyroid metastasis are quite peculiar clinical presentations. ACC is a malignant salivary gland-type tumour mostly found in the head and neck district, but that can arise from different organs. Due to its rarity, it can pose problems in the diagnostic and therapeutic management. A 72-year-old woman presented for a persistent non-productive cough. A computed tomography showed a lung mass. She underwent lung surgery, and the lesion was an ACC primitive of the lung. She developed hoarseness and ultrasound and cytology confirmed metastatic involvement of left thyroid lobe from ACC. A total thyroidectomy was performed, followed by radiotherapy. The present case highlights the need to be aware of possible metastatic thyroid localization of ACC originating in lower airways. This is a very rare event, and clinical and cytological findings must be carefully examined. It represents an opportunity to consider the current knowledge about ACC metastasis to thyroid.