Abstract Phosphorus is one of the most abundant minerals in the human body; it is required to maintain bone integrity and mineralization, in addition to other biological processes. Phosphorus is regulated by parathyroid hormone, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], and fibroblast growth factor 23 (FGF-23) in a complex set of processes that occur in the gut, skeleton, and kidneys. Different molecular mechanisms – overproduction of FGF-23 by tumors responsible for oncogenic osteomalacia, generation of an FGF-23 mutant that is resistant to cleavage […]

ABSTRACT Objective: The aim of this cross-sectional study was to estimate the prevalence of XLH in Paraná, a state in southern Brazil, and report the clinical features and complications of the disease. Materials and methods: We invited all endocrinologists (n = 205), nephrologists (n = 221), orthopedic surgeons (n = 1020), and pediatricians (n = 1000) in Paraná to fill out an electronic survey with information on patients with X-linked hypophosphatemia (XLH), and searched the records of the state’s health […]

Tumor-induced osteomalacia (TIO) is a rare paraneoplasic syndrome with overproduction of fibroblast growth factor 23 as a phosphaturic agent, leading to chronic hyperphosphaturia and hypophosphatemia, associated with inappropriately normal or low levels of 1,25-dihydroxyvitamin D. Diagnosis of this disease is often challenging. The following case report described a middle-aged man with symptoms of bone pain and severe muscle weakness, who was found to have TIO. The tumor responsible for the symptoms was localized on his thigh and its resection resulted […]

Oncogenic osteomalacia is a paraneoplastic syndrome usually induced by bone or soft tissue tumors. It is presented by the development of pain and fractures with hypophosphatemia, hyperphosphaturia, and inappropriate normal/low plasma 1,25(OH)2D3 concentration. After the removal of the tumor the complete resolution of all biochemical and clinical abnormalities is the main characteristic. A case of a 44-year-old female with difficulty in walking due to leg pain and generalized muscle weakness and hypophosphatemia, with relative hyperphosphaturia, is described. A whole-body 99mTc-sestamibi […]

Adult-onset hypophosphatemic osteomalacia is a rare disease characterized by hypophosphatemia, increased levels of alkaline phosphatase and decreased bone mass. Oral supplementation with phosphate and vitamin D is the main treatment and, in cases of oncogenic osteomalacia, tumor resection is mandatory. We report the case of a patient with hypophosphatemic osteomalacia of an unknown cause. Despite extensive search, no tumor was found. The patient was treated with phosphate for a long period and developed tertiary hyperparathyroidism. Serum PTH levels did not […]