Renal milk of calcium cysts refer to the appearance of a calcium precipitate found either within a calyceal diverticulum, that has lost communication with the collecting system, or within a simple renal cyst.
Renal milk of calcium cysts are typically asymptomatic.
- on erect or decubitus films, renal milk of calcium cysts have a characteristic crescentic opacity with a sharp upper border
- will change shape to a more oval-shaped opacity on supine projections
- dependent echogenic material within a hypoechoic cyst that demonstrates reverberation artefact
- posterior shadowing is present when large volumes of milk of calcium are present
- more common in the upper pole of the kidneys
Treatment and prognosis
Considered an incidental benign finding that does not require further treatment unless symptomatic.
On supine plain radiographs, a renal milk of calcium cyst may be mistaken for a renal calculus. Milk of calcium can also occur within the gallbladder.
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