Histology of Myositis ossificans mimics -: (A) Osteosarcoma, (B) Osteochondroma, (C) GCT, (D) Ewing's tumour
Answer is A. 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.