Adenoid cystic carcinoma of sinonasal origin masquerading as an intraconal lesion.

Adenoid cystic carcinoma is an uncommon tumour of the salivary glands, although affliction of mucin-producing glands present in the oral cavity, oropharynx and paranasal sinuses is not uncommon. Other possible sites are lacrimal, oesophagus, trachea-bronchial tree, lungs, uterus, cervix, prostate. These tumours have a tendency to be aggressive and most show invasion into the adjacent region. Adenoid cystic carcinoma contributes to about 0.3% of all sinonasal tumours.