BACKGROUND: Mazabraud\'s syndrome (MS) is a rare and slowly progressive benign disease characterized by the concurrent presence of fibrous dysplasia of bone and intramuscular myxoma, and is thought to be associated with mutations of the GNAS gene. To date, only about 100 cases of MS have been reported in the literature, but its standard treatment strategy remains unclear.
METHODS: We report two cases of MS in young women who underwent different treatments based on their symptoms and disease manifestations. The first patient, aged 37, received internal fixation and intravenous bisphosphonate for a pathological fracture of the right femoral neck, excision of a right vastus medialis myxoma was subsequently performed for pain control, and asymptomatic psoas myxomas were monitored without surgery. Genetic testing confirmed a GNAS gene mutation in this patient. The second patient, aged 24, underwent right vastus intermedius muscle myxoma resection, and conservative treatment for fibrous dysplasia of the ilium. These patients were followed-up for 17 months and 3 years, respectively, and are now in a stable condition.
CONCLUSIONS: Various treatments have been selected for MS patients who suffer different symptoms. The main treatment for myxomas is surgical resection, while fibrous dysplasia is selectively treated if the patient experiences pathological fracture or severe pain. However, given the documented instances of malignant transformation of fibrous dysplasia in individuals with MS, close follow-up is necessary.

The World Health Organization\'s (WHO) 2022 update on the classification of odontogenic and maxillofacial bone tumors has revolutionized diagnostic and treatment paradigms by integrating novel molecular insights. Fibro-osseous lesions of the maxillo-facial bones constitute a heterogeneous group encompassing fibrous dysplasia, Psammomatoid Ossifying Fibroma (PSOF), Juvenile Trabecular Ossifying Fibroma (JTOF), and other variants. Despite histological similarities, their distinct clinical manifestations and prognostic implications mandate precise differentiation. The intricacies of diagnosing fibro-osseous lesions pose challenges for pathologists, maxillofacial surgeons, dentists and oral surgeons, underscoring the importance of a systematic approach to ensure optimal patient management. Herein, we present two cases, fibrous dysplasia and Cemento-Ossifying Fibroma, detailing their clinical encounters and management strategies. Both patients provided informed consent for publishing their data and images, adhering to ethical guidelines.

Fibrous dysplasia (FD) is a rare, non-inherited, congenital bone disorder which may be monostotic or polyostotic. The polyostotic form may rarely present in syndromic forms when associated with extra-skeletal manifestations. Mazabraud syndrome is a rare syndrome consisting of polyostotic FD presenting with intramuscular myxomas. McCune-Albright syndrome is recognised by polyostotic FD, precocious puberty and \'café au lait\' spots. This report describes an adult patient with Mazabraud syndrome and a child with McCune-Albright syndrome.
UNASSIGNED: Radiographic findings are typical with bowing deformities, sclerotic, lucent or mixed lesions and bony expansion, often with endosteal scalloping. MRI is often non-contributory and may actually mimic a more aggressive process. Early detection and correct diagnosis allow for early preventative treatment and rehabilitation to prevent devastating neurological sequelae and disability.

Fibrous dysplasia (FD) is a rare benign skeletal disorder that replaces normal bone with fibrous tissue and immature woven bone. We present a case of a 13-year-old girl with right-sided facial swelling and craniofacial deformity since birth, accompanied by nasal obstruction and difficulty in breathing and swallowing. Computed tomography (CT) imaging revealed an expansile bony lesion with a ground-glass matrix involving multiple craniofacial bones. Histopathological examination confirmed the diagnosis of FD. Management involved regular monitoring and conservative measures, with surgical intervention reserved for symptomatic progression or cosmetic concerns. This case underscores the importance of considering FD in the differential diagnosis of craniofacial asymmetry and highlights the collaborative approach to patient care. Further research is needed to optimize management strategies and outcomes for pediatric patients with FD.

OBJECTIVE: In this study, our aim was to develop and validate the effectiveness of diverse radiomic models for distinguishing between gnathic fibrous dysplasia (FD) and ossifying fibroma (OF) before surgery.
METHODS: We enrolled 220 patients with confirmed FD or OF. We extracted radiomic features from nonenhanced CT images. Following dimensionality reduction and feature selection, we constructed radiomic models using logistic regression, support vector machine, random forest, light gradient boosting machine, and eXtreme gradient boosting. We then identified the best radiomic model using receiver operating characteristic (ROC) curve analysis. After combining radiomics features with clinical features, we developed a comprehensive model. ROC curve and decision curve analysis (DCA) demonstrated the models\' robustness and clinical value.
RESULTS: We extracted 1834 radiomic features from CT images, reduced them to eight valuable features, and achieved high predictive efficiency, with area under curves (AUC) exceeding 0.95 for all the models. Ultimately, our combined model, which integrates radiomic and clinical data, displayed superior discriminatory ability (AUC: training cohort 0.970; test cohort 0.967). DCA highlighted its optimal clinical efficacy.
CONCLUSIONS: Our combined model effectively differentiates between FD and OF, offering a noninvasive and efficient approach to clinical decision-making.

Fibrous dysplasia is a rare non-hereditary congenital condition characterized by 2 main forms: monostotic and polyostotic. Monostotic is the more common form, while polyostotic, often associated with a syndrome, is rarer. The case presented involves a 10-year-old patient who was diagnosed with polyostotic fibrous dysplasia accompanied by an endocrinopathy. This report explores the clinical and radiological aspects of this condition based on the patient\'s case.

Fibrous dysplasia (FD) poses a therapeutic challenge due to the dysregulated extracellular matrix (ECM) accumulation within affected bone tissues. In this study, we investigate the therapeutic potential of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) in managing FD by examining its effects on FD-derived cells in vitro. Our findings demonstrate that 1,25(OH)2D3 treatment attenuates the pro-fibrotic phenotype of FD-derived cells by suppressing the expression of key pro-fibrotic markers and inhibiting cell proliferation and migration. Moreover, 1,25(OH)2D3 enhances mineralization by attenuating pre-osteoblastic cellular hyperactivity and promoting maturation towards an osteocytic phenotype. These results offer valuable insights into potential treatments for FD, highlighting the role of 1,25(OH)2D3 in modulating the pathological properties of FD-derived cells.

Fibrous dysplasia (FD) is a mosaic skeletal disorder caused by somatic activating variants of GNAS encoding for Gαs and leading to excessive cyclic adenosine monophosphate signaling in bone-marrow stromal cells (BMSCs). The effect of Gαs activation in the BMSC transcriptome and how it influences FD lesion microenvironment are unclear. We analyzed changes induced by Gαs activation in the BMSC transcriptome and secretome. RNAseq analysis of differential gene expression of cultured BMSCs from patients with FD and healthy volunteers, and from an inducible mouse model of FD, was performed, and the transcriptomic profiles of both models were combined to build a robust FD BMSC genetic signature. Pathways related to Gαs activation, cytokine signaling, and extracellular matrix deposition were identified. To assess the modulation of several key secreted factors in FD pathogenesis, cytokines and other factors were measured in culture media. Cytokines were also screened in a collection of plasma samples from patients with FD, and positive correlations of several cytokines to their disease burden score, as well as to one another and bone turnover markers, were found. These data support the pro-inflammatory, pro-osteoclastic behavior of FD BMSCs and point to several cytokines and other secreted factors as possible therapeutic targets and/or circulating biomarkers for FD.

Fibrous dysplasia (FD) is a rare bone disorder characterized by the replacement of normal bone with benign fibro-osseous tissue. Developments in our understanding of the pathophysiology and treatment options are impeded by the lack of suitable research models. In this study, we developed an in vitro organotypic model capable of recapitulating key intrinsic and phenotypic properties of FD. Initially, transcriptomic profiling of individual cells isolated from patient lesional tissues unveiled intralesional molecular and cellular heterogeneity. Leveraging these insights, we established patient-derived organoids (PDOs) using primary cells obtained from patient FD lesions. Evaluation of PDOs demonstrated preservation of fibrosis-associated constituent cell types and transcriptional signatures observed in FD lesions. Additionally, PDOs retained distinct constellations of genomic and metabolic alterations characteristic of FD. Histological evaluation further corroborated the fidelity of PDOs in recapitulating important phenotypic features of FD that underscore their pathophysiological relevance. Our findings represent meaningful progress in the field, as they open up the possibility for in vitro modeling of rare bone lesions in a three-dimensional context and may signify the first step towards creating a personalized platform for research and therapeutic studies.

Craniofacial fibro-osseous lesions represent a diverse spectrum of pathologic conditions where fibrous tissue replaces healthy bone, resulting in the formation of irregular, woven bone. They are more commonly diagnosed in young people, with treatment strategies dependent on clinical behavior and skeletal maturity. This article discusses the examples of craniofacial fibro-osseous lesions, based on the latest classifications, along with their diagnostic criteria and management.