Adenoid cystic carcinoma of the base of the tongue metastasizing to the scalp.

Adenoid cystic carcinoma is a rare neoplasm that originates from secretory glands, most commonly from the salivary glands. We present a 76 year-old white man with a history of adenoid cystic carcinoma from the base of the tongue diagnosed 15 years prior to the development of the metastatic lesion on his mid-posterior scalp. The present case represents the second reported instance of an extracutaneous adenoid cystic carcinoma metastasizing to the scalp. Differentiating between a primary cutaneous adenoid cystic carcinoma and an extracutaneous adenoid cystic carcinoma metastasizing to cutaneous structures is crucial in determining prognosis and management.