Polycystic Echinococcosis of the Orbit

To report a case of polycystic echinococcosis of the orbit caused by Echinococcus oligarthrus. Interventional case report A 14-year-old girl presented with a massive proptosis of the right eye of 9 years duration and loss of vision. The eye was phthisic, and a cystic mass was palpable. Computed tomography scan showed closely packed multiple orbital cysts with destruction of the medial orbital wall. Surgical exploration was performed. The phthisic eye was enucleated. Dissection of the outer fibrous capsule yielded approximately 30 intact translucent white cysts of various sizes that were suggestive of polycystic echinococcosis. The diagnosis of echinococcosis was confirmed on histopathologic evaluation. The specific diagnosis of E oligarthrus was made on the basis of the presence of straight-backed hooks and central guards. Polycystic echinococcosis of the orbit caused by E oligarthrus is rare. It may be an entirely new entity or hitherto unrecognized form of orbital echinococcosis.