Orbital apex syndrome as a sign of unsuspected breast carcinoma.

Breast cancer, the most common form of cancer among women, rarely metastasizes to the paranasal sinuses and skull base. The disease usually proceeds insidiously, remaining asymptomatic until ocular symptoms appear. Orbital involvement is frequently seen in metastatic disease of the paranasal sinuses and skull base, but orbital apex syndrome is rare. Early presentation with clinical features of acute ethmoiditis can delay the diagnosis of metastatic disease. Here, we report the case of a 43-year-old woman with breast cancer who presented with orbital apex syndrome secondary to the skull base and paranasal sinus metastasis.