Tumors of bone

Bone tumors constitute a heterogeneous group of neoplasms of skeletal origin. Benign cartilage tumors include osteochondroma, subungual exostosis, bizarre parosteal osteochondromatous proliferation (BPOP), chondromas, synovial chondromatosis, chondroblastoma, and chondromyxoid fibroma. Ewing sarcomas, also known as primitive neuroectodermal tumors (PNET), are highly aggressive small cell round cell sarcomas showing varying degrees of neuroectodermal differentiation. Giant cell tumor of bone is a benign but locally aggressive tumor accounting for approximately 5% of all bone tumors. Cytogenetic analyses of bone tumors have demonstrated that most subtypes carry characteristic, sometimes tumor-specific, chromosomal aberrations that are useful for differential diagnostic purposes. Many of the tumor-specific chromosomal rearrangements are balanced translocations, and for the majority of them, the molecular consequences have been clarified, allowing the use of fluorescence in situ hybridization (FISH) or reverse transcription polymerase chain reaction (RT-PCR) to verify or exclude their presence preoperatively or before initiating chemotherapy.