This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney, Subject name: Medicine
Nephrocalnosis is seen in 
Select and explain. 
A. Sarcoidosis, B. Medullary cystic disease, C. Milk alkali syndrome, D. All the above
D: All the above
Answer: D: All the above 
Explanation: Medullary sponge kidney is one of several common causes of medullary nephrocalcinosis. Medullary nephrocalcinosis is defined as the deposition of calcium salts in the medulla of the kidney Nephrocalcinosis due to milk-alkali syndrome (MAS). Nephrocalcinosis is a pattern of renal injury characterized by abundant renal tubular and interstitial deposits of calcium phosphate. Renal dysfunction occurs early in the disease, and elevations in blood urea nitrogen and creatinine are required for the diagnosis Nephrocalcinosis and Nephrolithiasis due to Deranged Calcium Metabolism. Clinically, nephrocalcinosis occurs in about a third of the patients with hypercalcemia. Nephrocalcinosis in sarcoidosis is similar to that observed in primary hyperparathyroidism, vitamin D intoxication, and milk alkali syndrome. Ref Harrison20th edition pg 278