Autosomal recessive polycystic kidney disease is characterized by nonobstructive, bilateral, symmetrical dilatation and elongation of 10-90% of the renal collecting ducts, focally accounting for a wide variability of renal dysfunction. As the number of ducts involved increases, the kidneys enlarge. However, at autopsy, the reniform shape is maintained, because the abnormality is in the collecting ducts and the cysts are usually minute (< 3 mm). In older patients, cysts as large as 1 cm may be seen