In 22 cases of either adult polycystic liver (PLD) or polycystic kidney (APCD) disease, considered as one dominantly inherited entity, both diseases occurred together only once. Early microscopical cystic lesions that are typical of PLD were found in another case of APCD. In this medicolegal autopsy series the incidence of PLD was 0.05% and that of APCD 0.08%.

Cerebral haemorrhage or cerebral aneurysms were found in 50% of APCD cases but in none of the cases with only PLD (p<0.01). Of the cases with PLD, 50% had associated renal cysts and 10% of the cases with APCD had associated liver cysts. The same medicolegal autopsy material yielded a prospective series of 95 male cases, where, however, kidney cysts were normally present in over 50% and liver cysts in about 20% of the cases of similar age. Thus, a part of the association between cystic disease of the liver and kidney may have been based on the common occurrence of cysts in old age.

V. Meyenburg's complex was the microscopic alteration associated with cysts in PLD. It was associated as well with liver cysts in APCD suggesting that an intricate relation between PLD and APCD does occur in part of the cases, in this series characterized by large size APCD kidneys.

The results indicate that in adults PLD is an entity of its own, expressed in most of the cases independently of APCD.