[Input of genetic analyses in the differential diagnosis of kidney cysts].

The incidental finding of renal cysts is a common clinical situation given their high prevalence (~ 50 % after the age of 50) and the continuous improvement of abdomen imaging. Diagnosis is central to appropriately dictate the management of the patient. During the diagnostic work-up, it is important to consider (i) the aspect of the cysts, (ii) their number, (iii) and their location, as well as (iv) the age of the patient and his/her personal and familial medical history, (v) the presence of extra-renal manifestations, (vi) and the renal function (including the urinary sediment). Starting from an atypical clinical case characterized by a rapidly evolving chronic kidney disease associated with bilateral renal cysts, we review the classical diagnostic work-up of kidney cysts. As a conclusion, we propose a diagnostic algorithm including both acquired and hereditary nephropathies.