Medullary cystic disease and tubular basement membrane changes: clinicopathological characteristics of four patients

We describe herein the clinicopathological characteristics of four members of a family in which about half of the generation was affected by chronic renal failure after middle age. The inheritance was considered to be an autosomal dominant pattern. Clinically, neither sensorineural deafness nor ocular abnormalities were evident. In addition, there was neither hypokalemia nor hypercalcemia causing deterioration of renal function. Radiological examination revealed no cystic formation in the kidneys in any patients, although in two of them the examination was performed at the time of endstage renal disease. Histological examination showed chronic tubulo-interstitial damage with periglomerular fibrosis. On electron microscopy, characteristic but nonspecific thickening and lamination of tubular basement membrane were noted in all patients, while glomerular basement membrane was unremarkable in all patients. These findings suggest that our patients had medullary cystic disease. Demonstration of lamination and thickening of the tubular basement membrane by electron microscopy may be useful for the diagnosis of medullary cystic disease with undetectable cyst formation.