Abstract
Hyperphosphatemic familial tumoral calcinosis (HFTC) is a rare autosomal recessive disease caused by pathogenic variants in genes involved in phosphate homeostasis, and characterized by elevated serum phosphate levels and the development of ectopic calcifications. Management typically includes phosphate-lowering strategies and, when clinically necessary, surgical debulking of calcifications. Inflammatory flares occur variably and remain poorly understood. We report the case of a 27-yr-old woman with HFTC due to a homozygous GALNT3 mutation, who experienced recurrent painful flares, elevated inflammatory markers, and progressive calcinosis. Based on the hypothesis that HFTC may behave like an autoinflammatory syndrome, the patient was treated with canakinumab, an anti-interleukin-1 antibody, with 7 yr of follow-up to date. The treatment led to rapid and sustained clinical and biological remission, significant regression of calcified lesions without surgical intervention, and demonstrated good safety.