Abstract
Dedifferentiated adenoid cystic carcinoma（DACC）consists of a conventional neoplastic component with a highly-malignant transformed component. We present a case of DACC manifested in the palate. A 62-year-old woman visited our hospital with a complaint of contact pain on the left side of the palate. A 10-mm ulcer was seen at the left side of the hard palate. Enhanced CT revealed a tumor-like image extending into the nasal and paranasal cavity with destruction of bone. A biopsy specimen showed DACC. Metastases to the ipsilateral superior internal jugular and contralateral lateral retropharyngeal（Rouviere）lymph nodes and lung were revealed. Although concomitant chemoradiotherapy controlled the primary lesion and lymph node metastases, multiple metastases developed to the lung, liver and bone, resulting in death. The clinical and biological behavior of DACC is still unknown and so it is necessary to accumulate and analyze cases of DACC.
