In order to distinguish chondroma from other tumors, immunohistochemistry (IHC) was performed in 10 cases and showed positive for S100 and Vimentin in 10 cases, Ki-67 ≤ 3% in 3 and Ki-67 >3% in 2, positive for SOX-9 in 1, and negative for epithelial-membrane antigen (EMA), cytokeratin (CK), CK18, CD34 and glial fibrillary acidic protein (GFAP) in 10 cases. This evidence concerns the gene KRT18 and chondroma.