Published online Jul 28, 2015. doi: 10.4329/wjr.v7.i7.180
Peer-review started: February 27, 2015
First decision: March 20, 2015
Revised: April 14, 2015
Accepted: May 7, 2015
Article in press: May 8, 2015
Published online: July 28, 2015
Echinococcosis is a zoonotic disease. Liver is the most common site of involvement. Renal involvement is seen in 2% to 3% of patients. Computed tomography findings in renal hydatid typically include: a cyst with thick or calcified wall, unilocular cyst with detached membrane, a multiloculated cyst with mixed internal density and daughter cysts with lower density than maternal matrix. Rarely type IV hydatid cysts may mimic hypovascular renal cell carcinoma. We report a case of previously asymptomatic middle aged female who presented with mild intermittent pain and a complex renal lesion on imaging which was considered to be a hypovascular renal carcinoma or urothelial neoplasm. However, by serendipity, the patient had spontaneous hydatiduria and later was definitively diagnosed and stented. Hydatid disease should always be considered amongst the top differential diagnosis of an isolated “complex” renal lesion which remains indeterminate on imaging.
Core tip: Renal hydatid is generally secondary to disseminated hydatidoses or associated with hepatic involvement. Isolated renal involvement is far less common and reported in less than 5% of all hydatid cases. Without appropriate history a subset of renal hydatid, especially type 4 cyst may simulate cystic renal/urothelial neoplasm or other complex cystic lesions such as abscess. Radiologists must harbour a high index of suspicion and look for subtle imaging signs such as calcification and non enhancing “solid” component to include this diagnosis in the differential of complex renal lesion. Absence of relevant history or hepatic involvement should not prevent diagnosticians from entertaining this rare diagnosis.