PICTORIAL INTERLUDE

An unusual renal
cyst

Ralph Drosten
C F G Diedericks*
A J van N iekerk*

Department of Thoracic Imaging
Brigham and Women's Hospital

Boston, USA

'Prinsloo, Aitken & Partners
Union Hospital

Alberton

Case
presentation

A 35-year-old man presented to
hls doctor complaining of nonspecific
abdominal pain. His clinical examina-
tion and laboratory testing were
entirely normal.

The supine abdominal X-ray
(Fig. 1) demonstrated an ill-defined
focus of amorphous calcification
overlying the left renal lower pole. The
erect abdominal film (Fig. 2) demon-
strated a fluid/calcium level overlying
the left renal lower pole. Ultrasound
examination demonstrated a 22 x 25
mm well-defined cyst, with acoustic
shadowing, in the left renal lower pole
cortex.

-

Fig 1. Supine radiograph showing an ill-defined
radio-opaque calcific focus overlying the left renal
lower po/e.

These findings are consistent with
the diagnosis of milk of calcium cyst.

Discussion
Review of the major radiological

textbooks reveals little reference to this
entity in relation to the kidney. Milk of
calcium stones are tiny calculi that are
too small to be visualised radiograph-
ically as discrete entities, and appear as
milky opacities that layer out depen-
dently on upright or decubitis views.'

Fig. 2. Erect radiograph showing dependent layer-
ing of calcium in the left renal/ower pote.

Similar cysts may be found in the
breast.' The aetiology of this configu-
ration is unclear and may be sec-
ondary to previous infection or
haemorrhage/ or stasis.

The differential diagnosis includes
residual Pantopaque used in cyst
puncture' - rarely performed today.

References
I. Sutton D, Young JWR. A Concise Textbook of

Clinical Imaging. 2nd ed. Mosby, 1995: 653.
2. Granger RG, Allison DJ. Diagnostic Radiology.

Edinburgh: Churchill Livingstone, 1997: 1377,
2005,2011.

3. Dahnert W. Radiology Review Manual. 3rd ed.
Baltimore: Williams and Wilkins, 1996: 644.

50 SA JOURNAL OF RADIOLOGY • March 2002