Soft Tissue, Tumoural calcinosis

Tumoral calcinosis is the tumor-like deposition of calcium hydroxyapatite in periarticular soft tissues. It occurs in 3 forms: sporadic (most common), familial, and secondary (e.g. chronic renal failure). Most commonly, the subcutaneous tissue around large joints is involved. Microscopically, tumoral calcinosis appears as amorphous granular material (hydroxyapaptite crystals) within cystic spaces with variable degrees of “chunky” basophilic calcification. The cystic spaces are separated by thick fibrous septa and lined by histiocytes and sometimes multinucleated giant cells. The prognosis is benign in sporadic cases; familial forms may recur; secondary forms depend on treatment of the underlying condition.