THE PERICENTROMERIC INVERSION, INV (6)(P25Q13), IS A NOVEL DIAGNOSTICMARKER IN CHONDROMYXOID FIBROMA

Chondromyxoid fibroma is a benign bone tumor that arises most commonly in the metaphysis of long bones in young adults. The cytogenetic feat ures of this tumor are not well known. In this study, four chondromyxo id fibromas were karyotyped after short-term cell culture. All of the tumors contained clonal rearrangements of chromosome 6, and each of th ese rearrangements involved band 6q13. Two tumors contained a pericent romeric inversion, inv (6)(p25q13), which was described recently in ch ondromyxoid fibroma 6q13 rearrangements are not associated with other types of bone and soft tissue tumors, and the inv (6)(p25q13) is repor ted only in chondromyxoid fibroma. Hence, this cytogenetic marker migh t be helpful in distinguishing chondromyxoid fibroma from chondrosarco ma and other histologic mimics. The consistent occurrence of 6q13 rear rangements suggests a specific oncogenic mechanism in chondromyxoid fi broma, most likely involving oncogene activation.