Malignant degeneration of multilevel monostotic Paget's disease involving the thoracic spine: an unusual presentation.

Paget's disease is the second most common metabolic bone disease after osteoporosis and is characterized by abnormal bone turnover and remodeling that can lead to pain, pathological fracture, bony deformity and nerve compression syndromes. The lumbar region is the most commonly affected site within the spine followed by the thoracic and cervical spine. Even though the spine is affected very commonly in Paget's disease, malignant degeneration is exceptionally rare. Multilevel monostotic spine involvement due to Paget's disease is very uncommon. An unusual clinico-radiological manifestation of multilevel thoracic Paget's disease with sarcomatous degeneration presenting as a neurosurgical emergency is reported with a pertinent review of the literature.