Skull base tumor invading both cavernous sinuses. Adenoid cystic carcinoma mimicking a meningioma.

We present a case of an anterior skull base tumor invading both cavernous sinuses and extending into the right orbit in a 55 years old female. The radiological aspect was confusing, being highly suggestive for an extensively invasive meningioma. However, the orbital portion of the tumor, which was surgically removed, proved to be an adenoid cystic carcinoma. Some peculiar immunohistochemical findings were obvious, as well as a lack of continuity of the tumor with the local lacrimal gland. This is an unusual situation, when a lacrimal gland tumor spread along the cavernous sinus, cross the midline and approaches the contralateral orbit. Such local extension should be considered in the differential diagnosis of anterior skull base tumors.