Medial Rectus Epithelial Inclusion Cyst after Strabismus Surgery and Review of the Literature

Ophthalmic examination yielded the following results: vision: OD: 20/40, OS: 20/40; intraocular pressure (IOP): OD: 15 mm Hg, OS: 15 mm Hg. Eye position and motion were normal. Slit lamp examination showed a purple-hued cystic mass nasally of the left eye, extending to the orbit with clear verge and slight congestion (Figure 1). Orbital magnetic resonance imaging (MRI) revealed a mass in front of the tendons and muscle belly of left medial rectus in long T1-weighted images (WI) and T2WI signal without enhancement (Figure 2). Orbital CT showed a long strip cystic lesion within the left medial rectus area, 15 × 15 × 14 mm, and the Hounsfield unit value was 5 to 20 (Figure 3).