Diffuse interstitial pulmonary calcification (DIPC)—an unusual complication of several diseases including sarcoidosis, varicella, carcinomatosis, multiple myeloma, primary hyperparathyroidism, chronic renal disease with uremia, the "milk-alkali" syndrome—develops by either metastatic or dystrophic calcification. Metastatic calcification occurs in most hypercalcemic states, and the calcium deposits in normal visceral tissues, such as the lungs, kidneys, stomach, heart, and blood vessels. Dystrophic calcification, on the other hand, develops at normal serum calcium concentrations, and the calcium deposits in pathologic tissues, possibly by the phenomenon of calciphylaxis.
The symptoms and signs of DIPC are completely nonspecific and vary depending on the stage and progression of the disease. Once induced, the calcium continues to deposit in the alveolar septa of the lung and frequently incites the development of interstitial fibrosis. This may lead to restrictive lung dysfunction and mechanically stiff lungs. The clinical expressions of DIPC are frequently masked by the manifestations of the primary disease,
Holmes RA. Diffuse Interstitial Pulmonary Calcification. JAMA. 1974;230(7):1018–1019. doi:10.1001/jama.1974.03240070052034