Periosteal
chondroma is a benign cartilage
tumor that accounts for <2% of
chondromas. In the present study, four cases of periosteal
chondromas were cytogenetically investigated and studied for the expression of high-mobility group AT-hook 2 (HMGA2), mutations in
codons 132 of
isocitrate dehydrogenase (IDH)1 and 172 of IDH2; mutations -C228T and -C250T in the promoter region of
telomerase reverse transcriptase (TERT); and for methylation in the promoter regions of O-6-methylguanine-DNA
methyltransferase (MGMT) and
cellular retinol binding protein 1 (CRBP1).
Chromosome aberrations of 12q13-15 were found in two out of the four
tumors, while two had a normal karyotype. Two periosteal
chondromas carried the mutation IDH1R132C (CGT>TGT), and two carried the mutation IDH1R132L (CGT>CTT). However, none of the four
tumors had methylated MGMT and CRBP1 promoters or mutations at
codon 172 of IDH2. In addition, -C228T and -C250T mutations were not present in the promoter region of TERT, nor was HMGA2 demonstrated to be expressed. The present study indicated that in periosteal
chondromas, the involvement of 12q13-15 in structural rearrangements may be recurrent but that HMGA2 is not expressed. Additionally, the periosteal
chondromas investigated in the study carried a heterozygous IDH1R132 mutation, the MGMT and CRBP1 promoters were not methylated, and -C228T and -C250T mutations in the promoter region of TERT were absent.