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Q1: What are the radiological findings?
The radiograph of the left knee of the younger brother (fig 1; p 534) shows calcification in the periarticular soft tissues. Radiographs of both the elbows and forearms (figs 2 and 3; p 534) of the elder brother show calcification in the periarticular soft tissues and muscles.
Q2: What is the diagnosis?
The diagnosis is tumoral calcinosis (normophosphataemic type). The differential diagnosis includes other conditions causing soft tissue calcification—that is, myositis ossificans, calcified fracture haematoma, and systemic lupus erythematosus with secondary calcinosis.
Tumoral calcinosis is a genetic disorder of calcium-phosphorus metabolism.
It is inherited as an autosomal recessive trait.
The condition occurs secondarily in systemic disorders like chronic renal failure, systemic lupus erythematosus, and hyperparathyroidism.
The hip is the commonest site of involvement.
Q3: What is the pathogenesis and treatment of this condition?
The pathogenesis of tumoral calcinosis is not yet clearly established. It is said to occur as a result of deranged calcium-phosphorus metabolism. It can also occur as secondary to systemic disorders like chronic renal failure, hyperparathyroidism, and systemic lupus erythematosus. All these conditions also cause deranged calcium-phosphorus metabolism.
The treatment includes phosphate depletion in the diet (in hyperphosphataemic variant), topical steroid application, surgical excision of calcified deposits causing pain or limitation of joint movements, and curettage of sinuses discharging calcareous material.
Tumoral calcinosis is a genetic, metabolic disorder, characterised by deposition of calcium salts in the subcutaneous tissues of the body. The condition is inherited as an autosomal recessive trait.1 Common sites affected are hip, shoulder, elbow, and ankle joints with the hip joint being the site most commonly affected.2 Curiously the knees are usually spared.3 One of the boys described here had an involvement of the knee joint, which is rare.
The condition is said to occur as a result of deranged calcium-phosphorus metabolism with consequent hyperphosphataemia. Cases with normal serum phosphorus concentrations have also been reported and recently a pathological classification based on serum phosphorus concentrations has been suggested.4 Thus, patients can be classified as hyperphosphataemic or normophosphataemic.
In addition to subcutaneous calcium salt deposition, ophthalmic examination can reveal subretinal angioid streaks and dental radiograms may show pathognomic short, bulbous roots and partial obliteration of pulp cavities.5 These features were not seen in our cases. The calcification pattern in tumoral calcinosis is very characteristic with large, juxta-articular lesions, progressive enlargement over time, and a tendency to recur after surgical removal.2
Primary normophosphataemic tumoral calcinosis.