Histology of Myositis ossificans mimics -
Histologically myositis ossificans mimics osteosarcoma.
They can be differentiated by zone phenomenon :-

Osteogenic sarcoma → Central zone contains mature cells and peripheral zone contains more active immature cells.
Myositis ossificans → Central zone contains active immature cells and peripheral zone contains more mature cells.
Osteosarcoma
Osteochondroma
GCT
Ewing's tumour