congenital megacalycosis
Congenital megacalycosis is a rare renal malformation, characterized by non-obstructive dilation of the renal calyces as well as an increased calyceal number (12-20), with a normal renal pelvis, ureter, and bladder. It may be unilateral or bilateral and is usually asymptomatic unless complicated by nephrolithiasis and urinary tract infection.