Paget's Disease: Skeletal Manifestations and Effect of Bisphosphonates

Abstract

Background: Paget's disease of bone leads to change in the shape and size of the bone and results in reduced bone strength, leading to the complications of deformity, arthritis, and fracture. Due to unknown reasons, Paget's disease is rare in Asian descendants. We report the cases of Paget's disease who visited our institute for 15 years and reviewed the literatures.

Methods: We retrospectively reviewed the medical records and radiograms of 8 patients (6 female and 2 male) who were diagnosed as Paget's disease of bone. Diagnosis was confirmed by typical radiological feature in the involved skeletons and/or pathologic findings.

Results: Pelvis, skull and spine were three most frequently involved bones. All involved bones in our cases showed changes in shape and trabecular pattern which resulted in bowing of lower extremity, secondary osteoarthritis, compression fracture of spine and enlargement of skull. Mean follow time was 4.71 years and all patient were treated bisphosphonate (BP). Use of BP controlled the level of serum alkaline phosphatase level effectively.

Conclusions: We have reviewed eight patients who were previously diagnosed as Paget's disease of bone in our institute. We could identify typical radiologic and clinical findings such as bowing deformity of long bone, secondary osteoarthritis, compression fracture and osteomyelitis of mandible that deteriorated the quality of their living.

Keywords: Osteitis deformans; Paget's disease of bone.

Fig. 1. (A) General diploic widening and area of lytic defect (osteoporosis circumscripta) is shown in the occipital bone. (B, C) Increased bone density in mandible/maxilla and loss of alveolar bone are shown. The arrow indicates so called ‘cotton wool’ appearance, a pathognomonic finding of Paget's disease.

Fig. 2. (A) Multilevel spine involvement with compression fracture and enlargement of spinous processes and laminae is shown. (B) Increased bone formation and bone resorption activity is shown in three lumbar vertebrae with degeneration of intervertebral disc. (C) Suspicious bony lesion in the 3rd lumbar vertebrae was diagnosed as Paget's disease by computed tomography guided spinal bone biopsy. (A, D) Patient's bone biopsy of thoracic vertebrae: irregularly thickened bony trabeculae with osteoblastic and osteoclastic activity are shown (hematoxylin and eosin stain [H & E], ×100 magnification).

Fig. 3. (A) Coronal reconstructed computed tomography scan of the pelvis shows severe osteoarthritis of hip joint: loss of joint space and multiple subchondral bone cyst. Paget's disease involved right innominate bone. (B) Prominent varus deformity and thickened trabecular pattern are shown in the distal metaphysis and both condyles of right femur. (C, D) Thickening of anterior cortex resembling saber shin and varus deformity at the periarticular area are identified in the tibia.

Fig. 4. (A) Whole body bone scan shows hot uptakes in mandible, maxilla, calvarium, pelvis, both femora, and tibiae. Multiple small hot spots in both femoral shafts indicate multiple looser zones. (B) Enlarged views of the mid shaft of right femur (upper part 2013, lower part 2016). (C) Coxa vara and grade II anterolateral femoral bowing (reference line drawn from the tip of the greater trochanter to the center of trochlear notch passes through the medial cortex at the apex of bowing deformity) is shown. A beak like protrusion replaced smooth external expansion of the lateral cortex in the femur (encircled part is enlarged and shown in the lower part of column B). (D) Prophylactic femoral nailing was performed using a new technique which was developed for nailing in atypical femoral fracture associated femoral bowing.