Calcinosis

Definition

Calcinosis is the formation of calcium deposits in any soft tissue. Calcinosis is the accumulation of calcium below the outer layer of the skin. Calcinosis is the deposition of calcium in the skin, subcutaneous tissue, muscles and visceral organs.

Calcinosis commonly occurs in the skin, where it is known as calcinosis cutis or cutaneous calcification. Calcinosis cutis is divided into 5 major types according to the original cause of the symptoms. 

Types of calcinosis cutis

There are 5 types of calcinosis cutis: 1) Dystrophic calcification, 2) Metastatic calcification, 3) Tumoral calcinosis, 4) Idiopathic calcinosis and 5) Iatrogenic calcinosis.

Dystrophic calcification

The most common type of calcinosis is dystrophic calcification. This type of calcification can occur as a response to any soft tissue damage, including that involved in implantation of medical devices.

Occurs in an area where there is damaged, inflamed, neoplastic or necrotic skin. Tissue damage may be from mechanical, chemical, infectious or other factors. Normal serum calcium and phosphate levels exist.

Conditions that can cause calcinosis include:

• Trauma
• Acne
• Varicose veins
• Infections
• Tumours (pilomatrixoma, cysts, basal cell carcinomas and others)
• Connective tissue disease (dermatomyositis, systemic sclerosis, cutaneous lupus erythematosus)
• Panniculitis
• Inherited diseases of connective tissue (Ehlers-Danlos syndrome, Werner syndrome, Pseudoxanthoma elasticum, Rothmund-Thomson syndrome) 

Metastatic calcification

Metastatic calcification involves a systemic calcium excess imbalance, which can be caused by hypercalcemia, renal failure, milk-alkali syndrome, lack or excess of other minerals, or other etiologies.

Occurs in the setting of abnormal calcium and phosphate metabolism and is often associated with hypercalcaemia and/or hyperphosphataemia.

Conditions that can cause calcinosis include:

• Primary or secondary hyperparathyroidism
• Paraneoplastic hypercalcaemia
• Destructive bone disease, e.g. Paget disease
• Milk-alkali syndrome
• Excessive vitamin D intake
• Sarcoidosis
• Chronic renal failure
• Calciphylaxis

Tumoral calcinosis

The etiology of the rare condition of tumoral calcinosis is not entirely understood. It is generally characterized by large, globular calcifications near joints.

Idiopathic calcinosis cutis  

Generally occurs in the absence of any known tissue injury or systemic metabolic defect. Calcification is usually localised to one general area. 

Iatrogenic calcinosis cutis 

Calcinosis that arises secondary to a treatment or procedure, e.g. parenteral administration of calcium or phosphate, calcium deposition in newborns from repeated heel sticks.

Occurrence of calcinosis

Many parts of the body can be affected such as: fingers, arms, feet & knees. Pressure on the skin from these deposits can cause severe pain, ulcerations and infection if the calcium protrudes.

The signs and symptoms of calcinosis cutis vary according to the underlying cause. In many cases the lesions gradually develop and are often symptomless. The lesions usually appear as firm, whitish/ yellowish papules, plaques or nodules on the surface of the skin. A solitary lesion may develop, although multiple lesions are more common. Lesions may become tender and ulcerate, discharging chalk-like creamy material consisting mainly of calcium phosphate with a small amount of calcium carbonate. Fingertip lesions may be painful, while lesions at other sites may restrict joint mobility and limit movement due to stiffening of the skin. In severe cases cutaneous gangrene may occur.

Clinical laboratory investigation

Biochemical laboratory tests are performed to determine any metabolic abnormalities that may give rise to elevated calcium and phosphate levels.

Radiological examinations including plain film x-ray, CT scanning and bone scintigraphy are useful in demonstrating the extent of tissue calcification.

Biopsy of cutaneous lesions is used to confirm diagnosis. On histology, granules and deposits of calcium are seen in the dermis, often with a surrounding foreign-body giant cell reaction. Calcium deposits may also be found in subcutaneous tissue.


Treatment

Infection is treated with antibiotics administered orally or intravenously. In some cases, hospitalization is required when surgery is the only way to stop the infection.

The underlying cause of calcinosis cutis should be identified and treated accordingly. Medical therapy may be used to help relieve symptoms of the condition but are generally of limited and variable benefit.

Medications that may be tried include corticosteroids, probenecid, colchicine, sodium etidronate, diphosphonates, diltiazem, and magnesium and aluminium antacids.

Surgical removal of lesions is indicated when they:

• become very painful
• ulcerate and recurrent infections occur
• cause functional impairment.

Because surgical trauma may stimulate further calcification, it may be best to excise a small site before going ahead with a large excision. Recurrence is common after excision.
Depending on the underlying cause, a multidisciplinary team of physicians including nephrologist, rheumatologist, and haematologist may be needed to manage the condition.

Useful links

Calcinosis in Wikipedia 

Types of calcinosis (tabulated)

DermNet NZ (clinical)

Pictures of calcinosis

Clinical examples

Calcinosis - Patient's family forum 

Calcinosis - Josie's Adventure

Calcinosis - NLP Magic Valley