Methods

Morphologic technique. Four nephrectomy spec-imens were obtained at surgery from four patients with typical adult polycystic disease. Portions of cortex and medulla, including both cyst walls and more solid areas of each kidney, were fixed in neu-tral buffered formalin and embedded by standard procedures in paraffin for routine sections and in epoxy resin for semithin and thin sections. Six stan-dard (2 cm3) sized blocks from each kidney were embedded, and paraffin sections cut at 4 p. were stained with hematoxylin and eosin and with the Masson trichrome stain. Twelve different epoxy sections from each kidney were cut at random lev-els at approximately 1 p. and stained with a mixture of methylene blue and azure II, and thin sections were stained with uranyl acetate and lead citrate. Specimens for scanning electron microscopy were further fixed for 5 days in 2.5% glutaraldehyde in a 0.75 M cacodylate and hydrochloric acid buffer. Following fixation, the tissue was washed in the Cacodylate-hydrochloric acid buffer for 1.5 hours, de-hydrated through a series of graded alcohols to 100% ethanol, and then fractured in liquid nitrogen with a hammer and chisel. Subsequently, the tissue was transferred in fresh 100% ethanol to a Samdri critical-point dryer and dried with liquid carbon dioxide. The specimens were attached to aluminum stubs with a double-stick tape and placed in a Hum-mer I (Technics) for coating with gold-palladium. Specimens were examined and photographed with an ETEC Autoscan scanning electron microscope operating at an accelerating voltage of 20 kV. Ap-proximately 24 pieces of tissue 0.5 cm3 in size were examined from each kidney. In mounting, the tissue was so positioned that tubules could be scanned longitudinally along their lengths. After being scanned, the tissue was removed from the mounting stub, placed in propylene oxide for 1 hour, and then routinely prepared as above for semithin sectioning. This procedure was done on all cysts that presented occluding polyps so that it could be determined whether a given cyst was posi-tioned proximally (upstream) or distally to the polyp.

Case material: Case# 1. A 55-year-old male patient had a history of renal polycystic disease with renal failure of approximately 10 years' duration. He had been under treatment by hemodialysis for approximately 2 years. His serum creatinine concentration was 12.6 mg/dl. Embolization of the renal artery was attempted because of severe gross hematuria. Arteriography demonstrated a right re-nal mass. A right nephrectomy confirmed the pres-ence of renal cell carcinoma. His kidney weighed 1,405 g and was diffusely cystic. Subsequent clinical examination revealed no evidence of van Hippel-Lindau disease. The patient has since received a renal transplant.