Primary Intra-orbital Hydatid cyst: a case report of a rare cause of Exophthalmos

Abstract

Abstract Background: Hydatid disease is a tapeworm parasitic infection caused by Echinococcus granulosus that commonly affects the liver and lungs during its life cycle in the human body. Orbital involvement is a very rare occurrence and isolated orbital Echinococcosis is extremely rare. Case presentation: A 60-year-old female Eritrean woman presented with a 3 month history of painless protrusion and decreased vision of the left eye. Physical examination showed significantly decreased visual acuity of the left eye, left eye proptosis, and papilledema. Laboratory investigations were normal and orbital CT scan examination was suggestive of orbital hydatid cyst. After a two week course of oral albendazole, a medial anterior orbitotomy and cyst excision were performed. Post-operative biopsy was conclusive of an orbital hydatid cyst. She continued taking oral albendazole 400mg twice daily. On her postoperative follow-up, she had mild lid swelling and adduction deficit. There was significant improvement of the lid swelling and disc edema on the 21st postoperative day but the gain on the adduction deficit was minimal. Subsequent follow-up of the patient was not possible since the patient relocated back to Eritrea. Conclusion: Orbital hydatid cyst is an extremely rare presentation of human Echinococcus granulosus infection. However, it should be considered one of the differential diagnoses among patients living in an endemic area and presenting with proptosis of the eye. A preoperative course of anthelminthic followed by surgical excision of the cyst is the definitive management.