Table 3.

Classification of Osteosarcoma (OS).

Types	Subtypes	Frequency
Intramedullary	Conventional (osteoblastic/chondroblastic/fibroblastic)	80%
	Telangiectatic	<4%
	Low-grade	1–2%
	Small cell	1.5%
Cortex-associated	Parosteal	1–6%
	Periosteal	1–2%
	High-grade surface	<1%