Phosphaturic Mesenchymal Tumor
Elizabeth A. Montgomery, MD
Key Facts
Terminology
Synonym: Osteomalacia-associated mesenchymal tumor
Definition: Rare distinctive mesenchymal neoplasm associated with oncogenic osteomalacia
Clinical Issues
Complete excision cures intractable oncogenic osteomalacia
Most neoplasms behave in benign fashion
Microscopic Pathology
Spindled to stellate neoplastic cells
Elaborate microvasculature
Matrix production
Myxochondroid with variable hyalinization and flocculent mineralization
Osteoclast-like cells
Adipose tissue component
 Hematoxylin & eosin shows an admixture of multinucleated giant cells, spindle cells, flocculent grumous (“grungy”) material  , and hemosiderin  . |
 Hematoxylin & eosin shows another area of the neoplasm, with more prominent mineralization  . |
TERMINOLOGY
Abbreviations
Phosphaturic mesenchymal tumor (PMT)
Phosphaturic mesenchymal tumor (mixed connective tissue variant) PMT-MCT
Synonyms
Osteomalacia-associated mesenchymal tumor
Definitions
Rare distinctive mesenchymal neoplasm associated with oncogenic osteomalacia
Syndrome of osteomalacia due to phosphate wasting
