The tumors usually occur in adults.
These tumors are usually found in soft tissue but rarely may occur in bone.
The tumors are usually benign but rarely may be malignant.
Histologic components of a PMTMCT:
(1) mesenchymal cells that range from small and round to oval to spindle-shaped and which grow in sheets with occasional microcystic areas
(2) osteoclast-like giant cells, which may occur in clusters
(3) prominent blood vessels with a hemangiopericytoma-like pattern
(4) poorly formed cartilaginous areas
(5) dystrophic calcifications or metaplastic bone in the cartilaginous areas
Staining:
(1) The cartilaginous areas are colloidal-iron positive before and after hyaluronidase digestion.
(2) The tumor is vimentin positive but negative for many other markers.
