Fibrous dysplasia of occipital bone revealed by acute intracranial hypertension

Craniofacial fibrous dysplasia: A review of current literature

INTRODUCTION

Fibrous dysplasia (FD) is a rare genetic disease, in which normal bone is replaced by fibro-osseus tissue. Disease severity varies greatly from single monostotic lesions to widespread polyostotic disease. Craniofacial lesions are common and, due to the complex anatomy, can cause several disabling symptoms and local extra-skeletal complications. Since relatively rare, reported cases of craniofacial FD (CFD), specifically, are few and the appropriate management remains incompletely defined.

METHODOLOGY

We performed a systematic literature review following the PRISMA guidelines for articles considering CFD in the years 2010-2023. The search was conducted in the PubMed and OVID Medline libraries. Altogether 193 articles were retrieved and reviewed.

RESULTS

Overall, the clinical presentation of CFD is highly variable depending on site and extent of lesion, with pain, deformity or impairment of function being most common. Diagnoses are often incidental and primarily based on CT imaging, while more extensive imaging, genetic studies and lesion biopsies are reserved for unclear cases. Asymptomatic patients are suitable for observation, while symptomatic or widespread disease may require more active approach with medical or surgical treatment. Follow-up is encouraged in all patients to observe possible lesion reactivation, late-stage complications and, though rarely, malignant transformation. Management should be individually tailored with a multidisciplinary team and wholesome consideration of individual needs.

CONCLUSIONS

This review provides an updated discussion on craniofacial FD with focus on improved understanding of disease pathophysiology, appropriate line of surgical management, and new potential means of medical treatment.

Brain and eye involvement in McCune-Albright Syndrome: clinical and translational insights

McCune-Albright Syndrome (MAS) is a rare mosaic (post-zygotic) genetic disorder presenting with a broad continuum clinical spectrum. MAS arises from somatic, activating mutations in the GNAS gene, which induces a dysregulated Gsα-protein signaling in several tissues and an increased production of intracellular cyclic adenosine monophosphate (cAMP). Overall, MAS is a rare disorder affecting less than 1/100,000 children and, for this reason, data establishing genotype-phenotype correlations remain limited. Affected individuals clinically present with a variable combination of fibrous dysplasia of bone (FD), extra-skeletal manifestations (including cafeí-au-lait spots) and precocious puberty which might also be associated to broad hyperfunctioning endocrinopathies, and also gastrointestinal and cardiological involvement. Central nervous system (CNS) and eye involvement in MAS are among the less frequently described complications and remain largely uncharacterized. These rare complications mainly include neurodevelopmental abnormalities (e.g., delayed motor development, cognitive and language impairment), CNS anomalies (e.g., Chiari malformation type I) and a wide array of ophthalmological abnormalities often associated with vision loss. The pathophysiological mechanisms underlying abnormal neurological development have not been yet fully elucidated. The proposed mechanisms include a deleterious impact of chronically dysregulated Gsα-protein signaling on neurological function, or a secondary (damaging) effect of (antenatal and/or early postnatal) hypercortisolism on early pre- and post-natal CNS development. In this Review, we summarize the main neurological and ophthalmological features eventually associated with the MAS spectrum, also providing a detailed overview of the potential pathophysiological mechanisms underlying these clinical complications.

Optic disc edema in fibrous dysplasia/McCune-Albright syndrome: Prevalence, etiologies, and clinical implications

BACKGROUND

Fibrous dysplasia (FD) is a rare disorder of expansile fibro-osseous lesions that may be associated with extraskeletal features as part of McCune-Albright syndrome (MAS). Optic disc edema is a potentially serious ophthalmologic finding that has been rarely reported in patients with FD/MAS. The purpose of this study was to investigate the prevalence and potential clinical associations of optic disc edema in a large cohort.

METHODS

Clinical records were reviewed from subjects in an ongoing FD/MAS natural history study. Computed Tomography scans were evaluated for the presence of structural craniofacial abnormalities associated with optic disc edema, including Chiari I malformation and space-occupying lesions. Craniomorphometric analyses were performed to determine optic canal diameter and intracranial volume. Statistical analyses were performed to compare clinical and radiographic features between subjects with and without optic disc edema.

RESULTS

Optic disc edema was diagnosed in 7/187 subjects, for a prevalence of 3.7%. All subjects with optic disc edema were diagnosed before age 18 years and had mild, non-progressive disease. Radiographic structural abnormalities, including Chiari I malformation, aneurysmal bone cysts, and arachnoid cysts, were associated with higher odds of optic disc edema (odds ratio [OR] 24.3; 95% confidence interval [CI], 4.2 to 121.4; p < 0.01) (OR 18.0; 95% CI, 3.4 to 108.2; p < 0.01). Treatment with leuprolide, a gonadotropin releasing hormone analog, was also associated with optic disc edema (OR 26.0; 95% CI 3.3 to 177.5; p < 0.05). There was no significant association of optic disc edema with other MAS endocrinopathies, medications, optic canal diameter, or intracranial volume.

CONCLUSION

Optic disc edema is an uncommon but potentially serious complication of craniofacial FD, which may occur more frequently in pediatric patients and those with structural craniofacial abnormalities. The potential association of leuprolide therapy with optic disc edema in this population warrants further study.