Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome clinically characterized by bone pain, fractures and muscle weakness. It is caused by tumoral overproduction of fibroblast growth factor 23 (FGF23) that acts primarily at the proximal renal tubule, decreasing phosphate reabsorption and 1α-hydroxylation of 25 hydroxyvitamin D, thus producing hypophosphatemia and osteomalacia. Les...

Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome characterized biochemically by hypophosphatemia, excessive urinary phosphate excretion, low 1,25-dihydroxyvitamin D levels, and clinically by osteomalacia, pseudofractures, bone pain, fatigue, and muscle weakness. TIO can occur in patients with a variety of benign mesenchimal tumors (hemangiopericitomas, fibromas, angiosarcomas,...

1997 Vitamin D is converted in the liver by a vitamin D-25-hydroxylase (25-OHase) to form the major circulating form of vitamin D, 25-hydroxyvitamin D [25(OH)D]. There have been at least four different 25-OHases identified both in mitochrondia and in microsomes. 25(OH)D is, however, biologically inert and requires hydroxylation in the kidneys on carbon 1 by the CYP27B mitrochondrial enzyme 25-h...

A 30 year old Pakistani female patient with osteomalacia and coeliac disease presenting as an isolated dactylitis is reported.

Ribs from 3 preterm infants, who had died after prolonged intravenous feeding and artificial ventilation, were examined histologically and assessed for the degree of osteomalacia and osteoporosis in cancellous bone of the shaft. A grid counting technique was used. Osteomalacia was noted in all 3 cases but to a lesser degree than in classical vitamin D-deficient controls. Osteoporosis was pronou...