Table 1 Types of OS
From: Osteosarcoma: a review of current and future therapeutic approaches
1. Central OS | 2. Multifocal |
 a. Conventional | 3. Gnathic |
  i. Osteoblastic | 4. Surface OS |
  ii. Chondroblastic |   a. Periosteal |
  iii. Fibroblastic |   b. Parosteal |
 b. Epithelioid |   c. High-grade surface |
 c. Giant cell-rich |   d. Intracortical |
 d. Osteoblastoma-like | 5. Secondary OS |
 e. Small cell |  |
 f. Telangiectatic |  |
 g. Low-grade central |  |