Isolated Renal Hydatid Cyst: CT Imaging Findings

A 52-year-old male presented to the emergency department with a 5-month history of episodic left flank pain. The physical examination\udand laboratory tests suggested stone disease. Chest radiography and the neurological examination were unremarkable.\udUltrasonography revealed a multiloculated cystic lesion in the left kidney. Contrast-enhanced computed tomography (CT) revealed a\ud7 cm diameter multiloculated cyst arising from the left kidney with a thick capsule with well-defined borders, containing multiple,\udperipherally located, tiny daughter cysts (Figure 1a,b). This appearance was compatible with a WHO type 2 A hydatid cyst. No additional\udcystic lesions were found on abdominopelvic CT or chest X-ray. He underwent surgery and the diagnosis of hydatid disease was made\udhistopathologically.\udHydatid disease is a common zoonosis of ruminants in which humans are an intermediate host. The major radiological findings of hydatid\uddisease are unilocular, multilocular, or calcified cysts in located anywhere in the body (1). The sites most commonly affected by hydatid\udcysts are the liver, lungs, and central nervous system (2). Renal hydatid cysts are rare and occur in 2-3% of all cases (3).\udVon Sinner et al. developed a widely accepted classification of hydatid cysts based on their radiological appearance, describing four types\udof hydatid cyst (2,4); type 1 cysts are unilocular, well-defined, homogenous cysts without septations; type 2 cysts contain numerous\uddaughter cysts inside the mother cyst and are subdivided into type 2A (round daughter cysts located peripherally), type 2B (larger,\udirregular daughter cysts and thick internal septations in the mother cyst), and type 2C (high-attenuated round or oval lesions with\udinternal calcifications)-type 2 cysts may show capsular calcification; type 3 cysts are dead lesions that are calcified entirely; and type 4\udcysts are lesions complicated by rupture or superinfection. Rupture is seen in 50–90% of all cases (2).\udThe standard treatment for hydatid disease is surgical resection combined with medical treatment. Percutaneous drainage is used widely\udto treat hydatid cysts (5).\udIn conclusion, a renal hydatid cyst is a rare renal cystic lesion. CT is an important radiological method that can reveal the correct diagnosi