Calcinosis is calcification (deposits of calcium phosphate) that may occur in many different soft tissues.
Types of Calcinosis
Calcinosis occurs in a variety of local and systemic (throughout the body) conditions.
Calcium phosphate crystals have a remarkable tendency to aggregate into snowball-like clumps and are invariably associated with particular collagens. Collagens are fibrous, insoluble proteins found in the connective tissues, including skin, bone, ligaments, and cartilage. Collagen represents about 30 percent of the total body protein.
Classification of the types of calcinosis generally separates these conditions into those that result from long-standing hypercalcemia (meaning an excessive amount of calcium in the blood) and/or hyperphosphatemia (meaning an excessive amount of phosphorus in the blood), and those following some local abnormality in the affected tissues. The classifications are metastatic calcification and dystrophic calcification, respectfully.
Metastatic Calcification. Calcium deposits, which occur commonly in hypercalcemic states, are found in the kidney, stomach, lung, brain, eyes, skin, subcutaneous and periarticular (surrounding a joint) tissues, and arterial walls. This type of calcinosis is usually related to other underlying conditions, such as hyperparathyroidism, hypoparathyroidism or renal disease.
Tumoral calcinosis is included in this category because of its frequent elevation in serum phosphorus levels and occasional increase in serum calcium values. However, it is separated from other forms of metastatic calcification because there are no internal organs involved. This condition is characterized by the rapid development of large, multi-lobulated, calcific masses in the subcutaneous (under the skin) tissue and muscles surrounding the hips, shoulders, elbows, hands, and chest walls. It has been suggested that this condition is hereditary with a disturbance in the metabolism of phosphorus.
Dystrophic Calcification. Many restrict the use of the term calcinosis to those patients who have calcium deposits in the soft tissues but have no generalized disturbance in calcium or phosphorus metabolism. Dystrophic calcification is often seen at sites of previous inflammation or damage to the skin. Calcinosis has been associated with connective tissue disease, such as in systemic sclerosis (scleroderma) or polymyositis-dermatomyositis.
The standard method of detection of dystrophic calcification has been the plain X-ray. However, computed tomographic (CT) scanning has been reported to identify calcinosis in symptomatic, but radiographically normal areas.
A variety of local and regional sites of calcification have been associated with rheumatic complaints. Occasional calcification has followed corticosteroid injections. In addition to the common syndromes of the shoulder and hip, idiopathic calcific tendinitis and tenosynovitis produce calcific deposits.
Treatment of dystrophic calcification is varied. Numerous drugs, hormones, and a host of non-specific measures have been used unsuccessfully in the treatment of calcinosis.
Oral low-dose anti-coagulant therapy has been effective occasionally in preventing and reversing subcutaneous calcinosis.
Surgical excision of large masses may be helpful in selected instances.
Colchicine may be effective in reducing soft tissue inflammation surrounding such deposits, along with nonsteroidal anti-inflammatory drugs.
Treatment of metastatic calcification at present consists mainly of early surgical excision of the calcified masses, which rarely recur at the same site. In time, new deposits may appear around other joints.