[Primary retroperitoneal hydatid cyst].

Hydatid cysts cause diseases most frequently by localizing in the liver and the lungs. Hydatid cysts with retroperitoneal localization are very rare. A 45-year-old female patient presented to our hospital with complaints of back pain, weight loss, and fatigue. The computerized tomography (CT) revealed that the patient had a septated cystic lesion of about 8x7x6 cm localized in the posterior of the left kidney, in the paravertebral site causing destruction of the neighboring costa. During laparotomy, the wall of the cyst with retroperitoneal localization was partially excised and the remaining cavity was drained. The drain was removed on post-op day 5. The histopathological diagnosis was reported to be a hydatid cyst. No problems were seen during the follow-ups of the patient who was administered post-op albendazole. Hydatid cysts are an endemic disease in our country and it should be kept in mind that they also have atypical localizations.