Osteomalacia por tumor secretor de FGF-23

a case of oncogenic osteomalacia in a 50-year-old male is here presented. he suffered severe bone pain and marked muscular weakness of 4 years' duration. there were several vertebral deformities in the thoracic spine, bilateral fractures of the iliopubic branches, another fracture in the left ischiopubic branch, and a looser's zone in the right proximal tibia. an octreotide-tc scan allowed to identify a small tumor in the posterior aspect of the right knee. it was surgically removed. microscopically, it was a phosphaturic mesenchymal tumor-mixed connective tissue (pmt-mct). expression of fgf-23 was documented by immune-peroxidase staining. there was rapid improvement, with consolidation of the pelvic fractures and the tibial pseudo-fracture. the laboratory values returned to normal.