Hyperostosis With Hyperphosphatemia: Evidence of Familial Occurrence and Association With Tumoral Calcinosis

Hyperostosis with hyperphosphatemia was first described in 1970¹ and subsequently in eight additional patients.^2-5 It presents as recurrent painful swelling of the long bones associated with hyperphosphatemia, normal renal function and serum parathormone level, and radiologic evidence of cortical hyperostosis and periosteal reaction in affected bones. Still not described in standard pediatric textbooks, hyperostosis with hyperphosphatemia is often unrecognized, leading to delay in diagnosis and subjecting patients to unnecessary and potentially harmful diagnostic, therapeutic, and surgical procedures. This report describes two sisters and an unrelated girl with hyperostosis and hyperphosphatemia and reviews previous cases in the literature. For the first time, we document the condition's familial and possible Middle Eastern prevalence and confirm its association with tumoral calcinosis,⁶ which might represent a continuous spectrum of the same pathogenic mechanism.