Adenoid cystic carcinoma of the skull base.

Adenoid cystic carcinoma (ACC) is a slowly growing tumor with a particular tendency to infiltrate the surrounding tissue by perineural spread. The clinical diagnosis may prove difficult due to the submucons extension of the tumor, especially at the skull base. This article outlines the clinical characteristics, diagnostics, and treatment modalities in a series of 56 patients with an ACC in the head and neck diagnosed between 1970 and 1998 in 32 females and 24 males. The youngest patient was aged 24 years, the oldest 77 years. The average age was 54 years. In 16 patients the tumor originated in the paranasal sinuses or the nasopharynx and involved the skull base. As a rule, several months passed between the manifestation of the first symptoms such as pain, blocked nose, epistaxis, or diplopia and the initial clinical diagnosis. All patients received surgical treatment, however, complete microscopical resection could only be achieved in approximately one third of the cases. Therefore, nine patients were postoperatively treated with radiotherapy. The average survival rates of the patients with an ACC of the skull base were only 99 months as compared to 144 months in the patients without skull base involvement.