At autopsy, gross examination of a kidney in patients with autosomal recessive polycystic kidney disease reveals multiple minute cystic spaces throughout the capsular surfaces. Cut sections of the kidney show that these cystic structures are subcapsular extensions of radially oriented cylindrical or fusiform ectatic spaces, with poor corticomedullary differentiation due to the extension of the elongated and dilated collecting ducts from the medulla to the cortex.