Abstract
Hydatid cyst is a parasitic zoonosis caused by echinococcosis. Liver and lung are the two primarily affected organs. Primary mesenteric hydatid cyst is a rare event, and few cases have been reported globally. In this case report, we present the first documented case, to our knowledge, in Lebanon. The patient was a 49-year-old female who presented for acute worsening of a long-standing abdominal pain. The primary differential diagnosis was an ovarian cyst, for which urgent surgical excision was performed. Histopathological analysis showed a primary mesenteric hydatid cyst, thus providing the final diagnosis. This case highlights the diagnostic challenges that rare and atypical localizations of hydatid cysts present, and the importance of including echinococcosis in the differential diagnosis of abdominal cystic masses.