Pathological fracture of the femur in a patient with Paget's disease of bone: a case report

Paget's disease of bone is a benign disease characterized by exaggerated remodeling of the bone matrix after osteoclast-mediated bone destruction. Its etiology is still unknown, despite the fact that it was discovered and described in 1877, but genetic factors and environmental triggers were shown to play their part in the pathogenesis of the disease. The main clinical presentations of the disease are related to bone pain and deformities. Radiological diagnosis is the main detection tool, though many monostotic Paget's disease cases may remain undiagnosed. We present the case of an 81-year-old male patient admitted to the Clinic of Orthopedics, Emergency County Hospital, Timisoara, Romania, with intense pain and deformity of the upper left thigh. Radiological examination performed shows a complete fracture of the upper third diaphysis of the left femur with suggestive signs for Paget's disease of the bone therefore a biopsy was taken and the patient was treated by surgical realignment with favorable evolution. He was discharged 13 days after surgery. The biopsy of the bone revealed extensive bone remodeling with numerous osteoclasts and extensive bone matrix deposition, unevenly stained and unevenly mineralized and reverse cement lines, which are consistent with the diagnosis of Paget's disease of the bone. Histomorphometric analysis show intense matrix deposition with a highly active remodeling process. Computed tomography (CT) scans were performed three years later and show the extension of the disease into the lower half of the left femur.