Coenurus cerebralis cyst in the orbit of a ewe.

A 4-year-old Rahmani breed ewe was presented for surgery to the Veterinary Teaching Hospital, South Valley University, Egypt with enlargement and protrusion of the eye ball, blepharitis and congestion of the conjunctiva. On examination, a cyst 2.5 cm x 3.5 cm in diameter containing sandy fluid was detected in the perioptic nerve fat. Histopathological examination revealed that the epithelial lining of the conjunctiva was necrotic and severely infiltrated by neutrophils. The underlying connective tissue was oedematous, hyperaemic and severely infiltrated by neutrophils. Desquamation of the corneal epithelium was seen, together with oedema of the stroma. The tissue surrounding the cyst was compressed and the lacrimal glands revealed pressure atrophy. The muscular tissue was atrophied and infiltrated by fat cells. The cyst wall was lined with white scolices protruding from the inner wall. Based on the gross and histopathological characteristics of the cyst observed, the cyst was diagnosed as Coenurus cerebralis. This is the first report of orbital coenurosis in a sheep.