Calcinosis cutis is a comprehensive terminology for disorders characterised by deposition of calcium salts in the cutaneous and subcutaneous tissue. Based on etiology, it can be classified into: dystrophic, metastatic, idiopathic, iatrogenic, and calciphylaxis. Dystrophic calcinosis occurs following a necrotic process unrelated to serum calcium level. Metastatic calcification results from precipitation of calcium salts due to high calcium or phosphorus levels. Calciphylaxis denotes calcification of the small and medium-sized blood vessels, of the dermis or subcutaneous tissue usually in the setting of renal failure [1]. Tumoral calcinosis refers to a severe form of calcinosis involving deeper tissues, especially around joints leading to limitation of movement.

A 14-year-old boy presented with history of hard swellings in the skin around multiple joints for past two years. Some of them ulcerated to extrude chalky white material. There was restriction of movements at knees, shoulders and elbows. He did not have history or examination findings to suggest autoimmune connective tissue disorders, pancreatic disease, chronic renal failure, malignancy, trauma, medical intervention in the affected regions. His previous records showed normal calcium and phosphorus levels, and he was not on calcium or vitamin D supplementation. There was no family history of similar condition. He had undergone excision of a large lesion from right axilla but did not receive any oral or parenteral medications for treatment of lesions before presenting to us.

There were multiple hard swellings involving the skin and subcutaneous tissue around shoulder, elbow, hip, knee joint and neck on both sides (Fig. 1a). Range of movement of all large joints measured using a universal goniometer showed restriction of joint movements which was maximum at right knee joint (50 degrees) and right elbow (30 degrees) for extension. Restriction of movements at the knee joints had resulted in limping. The physical examination was otherwise unremarkable.

Blood counts, renal function, liver function parameters were normal. Average serum calcium and phosphorus level(fasting sample) after multiple measurements were normal (9.4 mg/dL and 4.8mg/dL, respectively).Vitamin D insufficiency (25-hydroxy vitamin D level 12ng/mL) and secondary hyper-parathyroidism (Serum PTH level 126 pg/mL) were present. Plasma levels of 1, 25- dihydroxy Vitamin D was normal. Anti-nuclear antibody (ANA), Anti ds-DNA, Anti neutrophil cytoplasmic antibody (ANCA), anti-centromere, anti scl-70 and U1RNP were normal. Radiographic skeletal survey showed multilobulated ‘cloud-like’soft tissue calcification around joints with normal joint morphology (Fig.1b,c). Sonographically there were no renal and ureteric calculi or nephrocalcinosis. He had undergone excision of a lesion from the axilla before presenting to us, and the histopathology report had shown multiple cysts filled with calcified deposits lined by histiocytes consistent with tumoral calcinosis.

Fig. 1 (a) periarticular hard swellings at right knee, (b) X-ray of right knee joint showing multiple "cloud- like" periarticular calcifications, (c) X-Ray showing periarticular calcifications at left axilla and neck along platysma, (d) X-Ray of left axilla after 6 months of treatment with sevelamer and low phosphorus diet showing decrease in extent of calcification at axilla and neck.

Differential diagnoses considered were disorders which cause dystrophic calcification (like infection, inflammatory processes, cutaneous neoplasm or connective tissue diseases), metastatic calcification (like hypercalcemia or hyperphos-phatemia) and secondary tumoral calcinosis due to chronic kidney disease. All these differentials were effectively excluded by evaluation. Final diagnosis of normophosphatemic idio-pathic tumoural calcinosis was made.

Multidisciplinary team including endocrinologist, ortho-paedician, paediatrician and physiatrist decided to start phosphate lowering medical management aiming to keep phos-phorus in the low normal range, with graded physiotherapy and follow up closely after obtaining patients consent. Along with a low phosphorus diet, sevelamer at a dose of 400 mg twice daily was given orally. Surgical correction of deformity was reserved for a later scenario if medical and physical measures failed.

After 6 months of follow upon therapy, he reported improvement in joint movements and limp had disappeared which were confirmed on examination. X-rays showed decrease in the size of calcifications at axilla, knee and neck (Fig. 1d), whereas the lesion in the elbows did not increase in size. Smaller lesions have disappeared also. During the one year of follow-up, while maintaining serum phosphorus level between 3.3mg/dL and 3.5 mg/dL, he reports no new skin lesions or movement restriction nor any adverse events related to therapy.

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