Premalignant conditions of bone

Werner, Rothmund-Thompson, and Bloom syndromes all present with characteristic cutaneous findings during childhood and a predisposition for highgrade osteosarcoma, often at unusual locations, such as the patella.Although each of these syndromes maps to a unique genetic locus, the gene products share significant sequence homology.The latter finding is intriguing given the clinical similarities between the syndromes.Osteosarcoma is typically a diagnosis of childhood among the congenital syndromes.In contrast, chondrosarcoma presenting as part of an inherited syndrome does so late in adult life and is discussed in the context of specific precursor lesions below. Sporadic premalignant lesions Paget's diseaseBoth benign and malignant neoplasms arise in the setting of Paget's disease.The incidence of sarcoma has been estimated at approximately 1%. [2][3][4][5] Osteosarcoma is by far the most common, and fibrosarcoma and chondrosarcoma are rarely observed.[3][4] At the Mayo Clinic, 73 sarcomas arising in bone affected by Paget's disease have been recorded.Osteosarcoma typically affects patients with polyostotic Paget's disease, with the pelvis, femur, humerus, and tibia most often affected.3,[6][7][8] With the exception of the spine, the location of the sarcomas parallels the distribution of Paget's disease.Osteosarcoma associated with Paget's disease occurs at a later age than sporadic osteosarcoma, reportedly affecting subjects during the sixth to seventh decades.4,9 The prognosis of sarcoma in a patient with Paget's disease is considerably worse than for similar primary tumors, 2,3,10 with the 5-year survival as low as 8%.The discrepancy is multifactorial, related to the age of the patients, inoperative sites, fracture, and delay in diagnosis because the underlying Paget's disease can mask the clinical and radiographic findings.