Metastatic Calcinosis Cutis Secondary to Selective Fibroblast Growth Factor Receptor Inhibitor: Rapid and Complete Regression after Blood Phosphate Normalization and Drug Withdrawal

Hyperphosphatemic Tumoral Calcinosis With Pemigatinib Use

“…10 Although adverse dermatological manifestations such as alopecia, dry skin, nail toxicity, and palmar-plantar erythrodysesthesia were reported with FGFR inhibitors, only 3 cases of ectopic calcification have been reported in the literature to date. 3,11,12 However with increasing use of FGFR inhibitors, more cases will likely occur and therefore recognition of tumoral calcinosis as a potential complication of these medications is important.…”

“…8 Phosphate-lowering therapies including a low phosphate diet and phosphate binders are the mainstay of treatment for hyperphosphatemia and have been successful in lowering serum phosphate in patients treated with FGFR inhibitors who develop hyperphosphatemia. 11,12 In the setting of familial tumoral calcinosis and other causes of ectopic calcification, additional therapies that have been used include acetazolamide 4 and J o u r n a l P r e -p r o o f probenecid 13 . Sodium thiosulphate has shown some success in those patients with chronic kidney disease.…”