Extraocular Muscles Involvement as the Initial Presentation in Metastatic Breast Cancer.

Orbital metastasis is a rare event, and metastatic disease affecting the extraocular muscles is an even less frequent complication of solid tumors. Herein, we report an unusual case of ptosis as the initial presentation of an invasive breast cancer. A 68-year-old woman presented with III and VI partial nerve paresis, secondary to a compressive retrobulbar mass. Magnetic resonance imaging revealed an infiltrative lesion involving the extraocular muscles. Tissue biopsy yielded a result compatible with metastasis to the orbit, with immunohistochemistry analysis suggesting breast as the primary organ. Mammography identified an area of architectural distortion; stereotactic wire-guided biopsy confirmed the result of the previous orbital biopsy. A positron emission tomography scan demonstrated disseminated disease. Palliative chemotherapy with bone-modulating agents and subsequent hormonal therapy was proposed. Unfortunately, the patient did not respond to therapy and died 38 months after diagnosis.