[Are simple renal cysts another manifestation of prelithiasis in infancy?]

Simple renal cysts are uncommon lesions in paediatric patients. In the absence of hypokalaemia or an increase in the production of NH+, the cause of simple renal cysts is unknown. Hepler, in 1930, suggested that they may be caused by a tubular obstruction. We prospectively studied the presence of hypercalciuria or hypocitraturia as well as the family history of urolithiasis in a group of children diagnosed sonographically with simple renal cysts. The average age of the 22 patients (12M, 10F) was 6.04 +/- 2.9 years at the time of diagnosis. The ultrasound examination had been requested due to urinary tract infection, abdominal pain, haematuria or other disorders. The cysts were slightly more frequent on the left side (54.5%). All were located in the upper kidney pole. 14 patients were found to have hypercalciuria and/or hypocitraturia (hypercalciuria n = 11, 50%). Thirteen families had history of renal stones. The metabolic abnormalities associated with calculi in children and/or family history of stones were present in 19 families (86.3%). Our hypothesis is that both entities, renal cysts, and genetic predisposition to kidney stones, are related.