KIDNEY - Medullary cystic (Sponge)

The cut surface of the kidney shows numerous cysts up to 3.0 to 4.0 mm in the papillae. The kidney is somewhat smaller than normal and the outer surface shows numerous healing scars; there appears to be an occasional small cyst present although this is unusual in this condition.
This was an incidental finding in a hypertensive woman who died from a ruptured myocardial infarct. This condition is said to be more common in men than in women and it usually appears in late middle-age. It may be associated with small renal calculi. The cysts are lined by columnar or cuboidal cells; the cause is unknown.