Diplopia Secondary to Gastric Adenocarcinoma Metastasis to the Superior Oblique Muscle.

While gastric cancer often metastasizes to the liver, lymph nodes, and lungs, skeletal muscle metastasis is a rare event. The most common primary tumor metastasizing to the extraocular structures is breast cancer. Gastric carcinoma metastatic to the extraocular muscles is a rare event announcing a spreading disease with a bad prognosis. Here, we report a case of an asymptomatic gastric carcinoma metastasizing to the superior oblique muscle diagnosed via an endoscopic endonasal biopsy.