Microscopic section shows several large cysts.
Cysts develop at any segment of the nephron and therefore may have variable epithelial lining. In the early stages of cyst development, the cysts are connected to the tubules from which they arise and the fluid content is glomerular filtrate. When the cyst diameter exceeds 2 mm, most detach from the patent tubule and the fluid content is derived from secretions of the actual lining epithelium. With time, the cysts enlarge and cause progressive damage to adjacent functioning nephrons. Relatively common, occurring in one in 500 to 1000 individuals.