This document discusses different cystic diseases of the kidneys through clinical imaging examples: - Simple renal cyst appears as a smooth-walled, fluid-filled mass on nephrotomogram. - Infantile polycystic kidney disease shows enlarged kidneys with characteristic streaky densities leading to calyceal tips and minimal distortion on excretory urogram in a young boy. - Medullary sponge kidney demonstrates multiple small, smoothly rounded calculi occurring in clusters in papillary tips on excretory urogram and fine linear striations of contrast producing a brush border pattern in another patient.

1. 10Cystic Diseases of the Kidneys

2. CLINICAL IMAGAGING
AN ATLAS OF DIFFERENTIAL DAIGNOSIS
EISENBERG
DR. Muhammad Bin Zulfiqar
PGR-FCPS III SIMS/SHL

3. • Fig GU 10-1 Simple renal cyst.
Nephrotomogram shows the smooth-walled,
fluid-filled mass (arrows).

4. • Fig GU 10-2 Infantile polycystic kidney disease.
Excretory urogram in a young boy with large,
palpable abdominal masses demonstrates
renal enlargement with characteristic streaky
densities leading to the calyceal tips. There is
only minimal distortion of the calyces.

5. • Fig GU 10-3 Medullary sponge kidney. (A) Excretory urogram
demonstrates multiple small, smoothly rounded calculi occurring in
clusters in the papillary tips of multiple renal pyramids. (B) In
another patient, the ectatic tubules appear as fine linear striations
of contrast producing the characteristic brush border pattern.

6. • Fig GU 10-4 Multicystic dysplastic kidney. (A)
Plain film of the abdomen demonstrates multiple
thin, curvilinear calcifications outlining the cysts.
(B) Retrograde pyelogram shows atresia of the
proximal ureter.10

7. • Fig GU 10-5 Medullary cystic disease. (A) A 4-minute
radiograph from an excretory urogram shows a normal-
sized kidney with a smooth margin, delayed contrast
excretion, and a poor but homogeneous nephrogram over
the entire kidney. (B) Tomogram taken at 10 minutes shows
opacification of the collecting system with mild blunting of
the calyces. The nephrogram is composed of many streaky
collections of contrast material radiating from the calyces
to the periphery. (C) Radiograph taken at 120 minutes
shows a highdensity nephrogram confined to the medulla.
This is probably caused by accumulation of contrast
material in dilated tubules. The cortex and the columns of
Bertin are recognizable as radiolucent areas.11