Recurrent malignant variant of phosphaturic mesenchymal tumor with oncogenic osteomalacia

Skeletal Radiol. 2001 Feb;30(2):99-103. doi: 10.1007/s002560000306.


Phosphaturic mesenchymal tumor is a rare neoplasm which causes osteomalacia or rickets. The tumor typically follows a benign clinical course. Even in the rare malignant cases, local recurrence and distant metastasis are uncommon. We report on an example of a malignant phosphaturic mesenchymal tumor which recurred several times over 16 years concurrently causing hypophosphatemia, bone pain, and osteomalacia. Following each surgery, symptoms and hypophosphatemia improved. The patient died of disease 17 years after the first surgery. Histologically, the initial tumor was composed of small spindle cells with clusters of giant cells, prominent blood vessels, poorly formed cartilaginous areas, and crystalline material. Cytological atypia was minimal. Following multiple recurrences, the tumor demonstrated areas of high-grade sarcoma exhibiting marked pleomorphism, numerous mitotic figures, and p53 overexpression. This case illustrates the potential lethality of incompletely removed phosphaturic mesenchymal tumors.

Publication types

  • Case Reports

MeSH terms

  • Bone Neoplasms / complications
  • Bone Neoplasms / diagnostic imaging*
  • Bone Neoplasms / pathology
  • Bone and Bones / diagnostic imaging
  • Female
  • Fractures, Spontaneous / etiology
  • Humans
  • Hypophosphatemia / etiology
  • Lymphatic Metastasis
  • Middle Aged
  • Neoplasm Recurrence, Local
  • Osteomalacia / diagnostic imaging
  • Osteomalacia / etiology*
  • Phosphates / urine*
  • Radiography
  • Sarcoma / complications
  • Sarcoma / diagnostic imaging*
  • Sarcoma / pathology
  • Sarcoma / secondary


  • Phosphates