To report a rare case of worm infestation of the orbit, which is uncommonly encountered and merits consideration among differential diagnoses of orbital masses.

Report of a case who presented with orbital mass, underwent orbitotomy and excisional biopsy and histopathologic examination of the lesion was performed.

A 19-year-old male with chief complaint of right eye protrusion since three months ago was visited. There was 3 millimeters of proptosis on the right side and the globe was displaced downward. He had no history of trauma and was otherwise healthy. Visual acuity was 20/20 OU and comprehensive ophthalmic exam was normal. CT scan revealed a well-defined, heterogeneous mass in superomedial orbit with approximate size of 2×1.5×1.5 cm, located between superior rectus/levator muscle complex and superior oblique muscle. The lesion had compressive effect on adjacent sclera, causing globe deformity and indentation. With clinical suspicion of a mass lesion, orbitotomy and excisional biopsy was performed. The lesion was cystic with firm adhesions to sclera, superior oblique and superior rectus/levator muscle complex. Meticulous dissection from sclera allowed us to resect the lesion without globe perforation, but the levator and superior oblique muscles were sacrificed. Inside the cystic lesion, there were several thread-like objects and some yellow-brown viscous fluid. Histopathologic examination showed the thread-like objects to be helminths, but the exact genus and species could not be identified. Postoperatively, systemic prednisolone and cephalexin were prescribed, but after pathologic report became available, cephalexin was replaced by albendazole. At the last follow up visit, 3 months after surgery, the patient had 20/20 visual acuity and complete ptosis of right upper lid, but there was no proptosis or signs of orbital inflammation.

Helminthiasis of the orbit is quite rare. It is important to consider worm infestations in the differential diagnosis of orbital masses.