Phosphaturic mesenchymal tumor is a benign

Benign

A benign tumor is a tumor that lacks the ability to metastasize. Common examples of benign tumors include moles and uterine fibroids.The term "benign" implies a mild and nonprogressive disease. Indeed, many kinds of benign tumors are harmless to human health...

 neoplasm of mesenchymal origin, that produces phosphatonin (fibroblast growth factor

Fibroblast growth factor

Fibroblast growth factors, or FGFs, are a family of growth factors involved in angiogenesis, wound healing, and embryonic development. The FGFs are heparin-binding proteins and interactions with cell-surface associated heparan sulfate proteoglycans have been shown to be essential for FGF signal...

 23). This tumor

Tumor

A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...

 may cause tumor-induced osteomalacia, a paraneoplastic syndrome

Paraneoplastic syndrome

A paraneoplastic syndrome is a disease or symptom that is the consequence of the presence of cancer in the body, but is not due to the local presence of cancer cells. These phenomena are mediated by humoral factors excreted by tumor cells or by an immune response against the tumor...

, by the secretion of phosphatonin, which has phosphaturic activity (by inhibition of renal tubular reabsorption of phosphate

Phosphate

A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...

 and renal conversion
of 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D).