GCTTS is a very common Benign tumor usually affecting the digits in females ( 2x more common) grossly it is a lobulated small (2-3 Cm.) yellowish mass.
Here in our case we can see :
- osteoclast like gaint cells with many bland looking nuclei.
- many mononuclear cells in the back ground.
- Not much inflammatory cells or hemosidren.
The differential here:
- pigmented villonodualr tenosynovitis – usually in large joints like knee with lots of hemosidren.
- other granulomatous lesions – many inflammatory cells.
- mononuclear cells stain with Desmin
- you may see necrosis , tumor thrombi on paraffin sections.
Neoplastic vs reactive nature is still one of the questions to be solved.