Microarchitectural parameters and bone mineral density in patients with tumour‐induced osteomalacia by HR‐pQCT and DXA

• Published in: Clinical endocrinology (Oxford) Vol. 95; no. 4; pp. 587 - 594
• Main Authors: Mendes, Danielle A. B., Coelho, Maria C. A., Gehrke, Bárbara, Pinho, Leandro K. J., Cardoso Lima, Luis F., Paranhos‐Neto, Francisco, Mendonça, Laura M. C., Farias, M. L. Fleiuss, Madeira, Miguel
• Format: Journal Article
• Language: English
• Published: Oxford Wiley Subscription Services, Inc 01.10.2021
• Subjects: Bone density; bone microarchitecture; Bone mineral density; Cancellous bone; Computed tomography; Cortical bone; Dual energy X-ray absorptiometry; Fractures; high‐resolution peripheral quantitative computed tomography; hypophosphatasia; Osteomalacia; Radius; Reabsorption; Spine (lumbar); Tibia; Tumors; Vitamin D
• ISSN: 0300-0664; 1365-2265; 1365-2265
• DOI: 10.1111/cen.14533

Introduction Tumour‐induced osteomalacia (TIO) is a rare paraneoplastic condition characterised by decreased tubular phosphate reabsorption. The purpose of this study is to evaluate bone mineral density (BMD) and microarchitecture in six TIO patients, compared with 18 healthy controls. Methods Volumetric BMD and microarchitecture were evaluated by high‐resolution peripheral quantitative computed tomography (HR‐pQCT), and areal BMD by dual‐energy X‐ray absorptiometry (DXA). Differences between groups were significant for p < .05. Results All TIO subjects were healthy until the development of diffuse bone pain and multiple skeletal fractures and deformities. At baseline, sPi and TmPi/GFR were low and patients were on vitamin D and phosphate replacement at the study. Compared with controls, TIO patients had lower aBMD at lumbar spine and hip, and lower vBMD at trabecular, cortical and entire bone, at distal radius (R) and distal tibia (T): trabecular vBMD (R = 118.3 × 177.1; T = 72.3 × 161.3 gHA/cm3); cortical vBMD (R = 782.3 × 866.5; T = 789.1 × 900.9 gHA/cm3); total region vBMD (R = 234.5 × 317; T = 167.1 × 295.8 gHA/cm3). Bone microarchitecture was very heterogeneous among patients and significantly different from controls: lower cortical thickness (R = 0.59 × 0.80; T = 0.90 × 1.31 mm), bone volume‐to‐total volume ratio (R = 0.09 × 0.14; T = 0.06 × 0.13) and Tb.N (R = 1.46 × 2.10; T = 0.93 × 1.96 mm−1) and also higher Tb.Sp (R = 0.70 × 0.41; T = 1.28 × 0.45 mm) and Tb.1/N.SD (R = 0.42 × 0.18; T = 0.87 × 0.20 mm). Conclusion In this original study of TIO patients, DXA and HR‐pQCT evaluation identified lower areal and volumetric BMD and severely impaired microarchitecture at cortical and trabecular bones, which probably contribute to bone fragility and fractures.