Primary adenoid cystic carcinoma of the orbital apex.

Adenoid cystic carcinoma is an uncommon malignant tumor of epithelial origin typically arising from salivary glands. Orbital involvement may occur via direct or perineural spread from a lacrimal gland or sinonasal source. Primary orbital adenoid cystic carcinoma without involvement of the lacrimal gland is rare. The authors report a 53-year-old woman who was examined for insidious monocular vision loss and was found to have a primary adenoid cystic carcinoma of the orbital apex and cavernous sinus. Systemic workup for a primary source, including ipsilateral lacrimal gland biopsy, was negative. One must maintain a high index of suspicion for adenoid cystic carcinoma when evaluating orbital tumors.