Tumoral calcinosis: Diffuse multifocal form in hemodialysis patients. Two case reports.

Orthopedic surgeons are often consulted for diagnosis of MASS syndrome, imaging showing periarticular calcification, or joint stiffness. Such presentations in a dialyzed patient should suggest tumoral calcinosis, which is a rare complication of dialysis, often diagnosed wrongly or late. It is often associated with calcium phosphate balance disorder, in which treatment is difficult and must take account of known contributing factors: severe hyperparathyroidism, increased phosphocalcic product, therapeutic calcium and vitamin D overload, and bone turnover slowed for varying reasons. We report a clinical, radiological and therapeutic description of two cases of tumoral calcinosis, which consists in deposits of hydroxyapatite, the crystalline form of calcium phosphate, in diffuse multifocal periarticular locations, inducing both esthetic and functional damage.