Which condition involves the deposition of calcium salts within kidney tissue?

Nephrocalcinosis is a condition characterized by the deposition of calcium salts in the renal parenchyma, which includes kidney tissue. This condition typically arises due to various disorders that lead to increased calcium levels in the blood or urine, such as hyperparathyroidism or renal tubular acidosis. The accumulation of these calcium deposits can disrupt the normal architecture of the kidney and may affect its function.

In nephrocalcinosis, the ultrasound may reveal increased echogenicity of the renal cortex or medulla due to the presence of these calcium deposits, which can help in the diagnosis of this condition. Recognizing nephrocalcinosis is crucial because it can lead to complications such as impaired renal function or the formation of renal calculi, which may further complicate the patient's condition.

Other conditions listed, although related to kidney pathology, do not specifically involve the direct deposition of calcium salts within the kidney tissue itself, which is the defining feature of nephrocalcinosis.