Osteomalacia inducida por tumor

The tumor-induced osteomalacia is a paraneoplastic syndrome secondary in most cases to tumors of mesenchymal origin. It is characterized by increased lost of urinary phosphate by the inhibitory effect exerted by the fibroblast growth factor 23 on phosphorus transport in the proximal renal tubule. Should be suspected in a patient with weakness and generalized muscle in addition to hypophosphatemia, normocalcemia, elevated alkaline phosphatase and normal serum 25-hydroxyvitamin D and PTH. The definitive treatment of the disease is surgical resection of the tumor. When the primary tumor is unknown or is not possible the surgical treatment should be initiated replacement of phosphorus and calcitriol. This paper presents the first case of a patient with tumor-induced osteomalacia associated with lobular breast cancer.