Renal hydatid cyst; a rare infectious disease.

Hydatid cyst is one of the most important zoonotic diseases that is caused by Echinococcus granulosus. Infection is transferred through the oral-fecal pathway by eggs of the parasite and more by eating vegetables and food contaminated with dog stool containing eggs of the parasite. Hydatid cyst can be made in liver, lung and rarely in heart, breast, thyroid, soft tissue of neck and kidney. Hydatid cyst of the kidney is a rare disease which may have no symptoms for years. In this case report, the patient has had a typical cyst in the left kidney for years that it seems to be silent for long time in a woman with ambiguous left flank pain whom went to a physician, and after complementary examinations, finally a typical hydatid cyst was diagnosed with the size of 93 × 120 mm in left kidney.