An Atypical Case of Microphthalmos With Cyst: Cyst Masquerading as Phthisical Eye

A 6-year-old boy diagnosed with congenital microphthalmic OS was referred for prosthetic eye fitting. He was otherwise healthy without known congenital anomalies. His visual acuity was 20/20 in the OD and no light perception in the OS. His disfigured OS with a conjunctivalized opaque cornea appeared smaller than his OD. He had left esotropia with severely restricted ductions in all directions of gaze. The preoperative orbital MRI of the patient revealed a small orbital cyst posteroinferior to the OS. Because the patient could not tolerate the prosthetic eye worn over his disfigured eye, evisceration was planned. During the surgery, blunt dissection of the conjunctiva and Tenon's capsule uncovered a large orbital cyst that was misdiagnosed as phthisis bulbi preoperatively based on the clinical examination and imaging findings. The structure that was thought to be an orbital cyst on orbital MRI was the microphthalmic eye. Enucleation with cyst excision was performed. Patient had uneventful postoperative course and has been wearing an artificial eye for 1 year since surgery.