Skeletal involvement in tumor-induced osteomalacia

Area of Science:

• Endocrinology
• Oncology
• Bone Metabolism

Background:

• Tumor-induced osteomalacia (TIO) is an ultrarare paraneoplastic syndrome.
• It involves abnormal phosphate and vitamin D metabolism due to fibroblast growth factor 23 (FGF23) overproduction by mesenchymal tumors.
• TIO leads to skeletal symptoms and fractures due to adverse effects on bone.

Purpose of the Study:

• To describe the characteristics of TIO, including tumor histology, bone density, and bone quality.
• To evaluate the impact of tumor removal on biochemical and bone parameters.
• To highlight the long-term implications for patients with TIO.

Main Methods:

• Histological examination of bone biopsy samples.
• Assessment of areal bone mineral density (DXA) and trabecular bone score.
• Evaluation of bone microarchitecture using high-resolution peripheral quantitative computed tomography (HR-pQCT).

Main Results:

• Tumor histology shows specific features, with osteoid accumulation and prolonged mineralization lag time in bone biopsies.
• Patients with TIO exhibit significantly reduced bone mineral density and impaired bone quality (trabecular and cortical).
• Surgical tumor removal leads to complete reversion of biochemical abnormalities and significant short-term improvement in bone mineral density.

Conclusions:

• Surgical resection is the definitive treatment for TIO, resolving metabolic abnormalities.
• Bone mineral density improves post-surgery, though peripheral microstructural parameters may take longer to recover.
• Long-term quality-of-life outcomes, especially concerning fractures, require further investigation in TIO patients.