Diagnosis of bone mineral disorders (MCI) is an urgent task in pediatrics. Of particular importance is the timely visualization of destructive changes in bone tissue, leading to significant deformations and impairment of the quality of life of patients. At the moment, there are no unified algorithms for radiological examination of children with chronic kidney disease (CKD), allowing early detection of disorders of mineral and bone metabolism. This clinical example demonstrates the difficulties of diagnosing a brown tumor in a child with primary type I hyperoxaluria. Along with this, the effectiveness of methods of radiation diagnostics in the protocol of dynamic observation of patients with the syndrome of mineral and bone disorders in chronic kidney disease (MCD-CKD) is presented.