Fibrous dysplasia and cherubism

Area of Science:

• Orthopedics
• Genetics
• Pathology

Background:

• Fibrous dysplasia (FD) is a non-malignant fibro-osseous lesion characterized by the replacement of normal bone with fibrous and immature bone tissue.
• The genetic basis involves post-natal mutations in the GNAS1 gene, leading to uncontrolled mesenchymal cell proliferation and abnormal bone formation.
• Cherubism is a hereditary subtype caused by SH3BP2 gene mutations, presenting in monostotic or polyostotic forms, with the latter potentially linked to endocrine issues.

Purpose of the Study:

• To review the current understanding of fibrous dysplasia (FD) pathogenesis, clinical presentation, and management strategies.
• To discuss the controversies and individualized approaches in treating craniofacial FD, particularly in polyostotic forms.
• To highlight emerging therapeutic avenues, including bisphosphonates, minimally invasive surgery, and future genetic/stem cell therapies.

Main Methods:

• Literature review of fibrous dysplasia pathogenesis, genetics, and clinical management.
• Analysis of surgical and conservative treatment modalities for monostotic and polyostotic FD.
• Evaluation of current research on bisphosphonates, endoscopic surgery, and genetic/stem cell therapies for FD.

Main Results:

• FD management is controversial, with surgical excision being definitive but often impractical or deforming for polyostotic cases.
• Conservative approaches like aesthetic recontouring, orthodontic correction, and watchful waiting are often preferred for young patients.
• Nerve compression, especially optic nerve involvement, requires careful monitoring and timely, minimally invasive decompression if symptomatic.

Conclusions:

• Individualized treatment plans are crucial for craniofacial FD, balancing surgical intervention with conservative management and regular follow-up.
• Emerging treatments like bisphosphonates and advancements in surgical techniques offer improved prospects for FD management.
• Continued research into genetic factors and stem cell therapy holds potential for future breakthroughs in understanding and treating FD.