Incidence and Prevalence of Fibrous Dysplasia/McCune-Albright Syndrome: A Nationwide Registry-Based Study in Denmark.

CONTEXT: Fibrous dysplasia/McCune-Albright syndrome (FD/MAS) is a rare genetic disorder. Incidence and prevalence are not well-studied. Epidemiological research is complicated by the rarity of FD/MAS, absence of registries, heterogeneous presentation, and possibly asymptomatic phenotype. FD/MAS may present with FGF23-mediated hypophosphatemia, of which the epidemiology is also unclear. OBJECTIVE: Evaluate incidence and prevalence of FD/MAS and FD/MAS-related hypophosphatemia. METHODS: This cohort study based on the nationwide Danish National Patient Registry from 1995-2018, included patients identified by ICD-10 codes M85.0 (monostotic FD [MFD]) and Q78.1 (polyostotic FD [PFD]/MAS). Incidence rates and prevalence were calculated and stratified by sex, age, calendar period, and diagnosis code. Cases were screened for FD-associated hypophosphatemia by diagnosis code E.83 (disorder of mineral metabolism) and dispatched vitamin D analogues. RESULTS: A total of 408 patients were identified, 269 with MFD (66%), 139 with PFD/MAS (34%), comparable between sexes. Incidence of FD/MAS demonstrated increasing secular trend with a rate of 3.6 per 1 000 000 person-years (95% CI: 2.9, 4.5) in 2015-2018. Incidence peaked between age 11 and 20. Prevalence of FD/MAS increased over time to 61.0 (95% CI: 54.6, 67.4) per 1 000 000 persons in 2018. The incidence rate of MFD was 1.5-fold that of PFD/MAS in the first decade, rising to 2.5-fold in the last decade. No FD/MAS cases were registered with diagnosis code or treatment for hypophosphatemia. CONCLUSION: FD/MAS is rare, diagnosis peaks during adolescence without sex predominance, and MFD is most prevalent. Hypophosphatemia may be underdiagnosed and undertreated, or it may be underregistered, comparing this study to literature.

Value of rare diseases reference centers: impact on diagnosis and access to specialized care in fibrous dysplasia of bone.

INTRODUCTION: Reference Centers and Rare Disease Health Networks aim to improve the management of patients with rare diseases. The French reference center for Fibrous Dysplasia was certified in 2006. OBJECTIVE: The objective of our study was to assess the effectiveness of our reference center since its constitution. METHODS: In a retrospective cohort study, we compared the activity of our center, including the time elapsed between access to the center and the diagnostic delay of patients with Fibrous Dysplasia between two periods, 1994-2006 (before certification) and 2007-2019 (after certification). Data were extracted from patients' records (Easily®). Wilcoxon and Fisher tests were performed, using R®. RESULTS: Our cohort included 527 patients with Fibrous Dysplasia/Mc Cune Albright syndrome. The activity of the Fibrous Dysplasia center increased from 139 patients in the first period (1994-2006) to an additional 388 patients for the second period (2007-2019). Mean time elapsed to diagnosis of Fibrous Dysplasia was 1.5 years before 2007 and 1.9 years after 2007 (p = 0.12). Diagnosis was made before referral in over 80% of patients. There was a non-significant decrease in the number of patients with delayed diagnosis: 37 patients (44%) in the first period had a diagnostic delay and 94 patients (33%) in the second period (p = 0.07). Patients were referred to our center on average 6.8 years (before 2007) and 7.9 years (after 2007) after their diagnosis (p = 0.77). CONCLUSION: Healthcare organization with reference centers significantly impacted the management of patients with Fibrous Dysplasia/Mc Cune Albright syndrome, with a substantial increase in the activity of our center, that roughly tripled since certification. This healthcare organization was also associated with a trend toward decreasing diagnostic delay. However, diagnostic delay affected more than a third of patients and the time to access to the center remained extended (≈7-8 years after diagnosis). The current challenge lies in informing primary care providers and patients about education to rare diseases and existence of reference centers for earlier and more effective specialized management.

Coxa Vara Deformity in Fibrous Dysplasia/McCune-Albright Syndrome: Prevalence, Natural History and Risk Factors: A Two-Center Study.

This study aimed to evaluate the prevalence of and risk factors for coxa vara deformity in patients with fibrous dysplasia/McCune-Albright syndrome (FD/MAS). This study was conducted at the National Institutes of Health and Leiden University Medical Center. All patients with any subtype of FD/MAS, FD involving the proximal femur, one or more X-rays available and age <30 years were included. X-rays were scored for the neck-shaft angle (NSA). Varus deformity was defined as NSA <110 degrees or >10 degrees below age-specific values. Risk factors for deformity were assessed by nested case-control analysis, comparing patients and femurs with and without deformity, and by linear mixed effects model, modeling temporal NSA decrease (the natural course of the NSA) in non-operated femurs with two or more X-rays. Assessed variables included growth hormone excess, hyperthyroidism, hypophosphatemia, >25% of the femur affected, calcar destruction, radiolucency, and bilateral involvement. In total 180 patients were studied, 57% female. Mean ± SD baseline age was 13.6 ± 7.5 years; median follow-up 5.4 (interquartile range [IQR], 11.1) years. Sixty-three percent (63%) were diagnosed with MAS. A total of 94 patients were affected bilaterally; 274 FD femurs were analyzed; 99 femurs had a varus deformity (36%). In the nested case-control analysis, risk factors were as follows: presence of MAS (p < 0.001), hyperthyroidism (p < 0.001), hypophosphatemia (p < 0.001), high percentage of femur affected (p < 0.001), and calcar destruction (p < 0.001). The linear mixed effects model included 114 femurs, identified risk factors were: growth hormone excess (ß = 7.2, p = 0.013), hyperthyroidism (ß = 11.3, p < 0.001), >25% of the femur affected (ß = 13.2, p = 0.046), calcar destruction (ß = 8.3, p = 0.004), radiolucency (ß = 3.9, p = 0.009), and bilateral involvement (ß = 9.8, p = 0.010). Visual inspection of the graph of the model demonstrated most progression of deformity if NSA <120 degrees with age < 15 years. In conclusion, in tertiary care centers, the prevalence of FD/MAS coxa vara deformity was 36%. Risk factors included presence of MAS, high percentage of femur affected, calcar destruction, radiolucency, NSA <120 degrees and age < 15 years. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Risk of developing spontaneous MRONJ in fibrous dysplasia patients treated with bisphosphonates: a systematic review of the literature.

OBJECTIVE: The objective of this systematic review was to evaluate the risks of medication-related osteonecrosis of the jaw (MRONJ) in fibrous dysplasia (FD) and McCune-Albright syndrome (MAS) patients treated with bisphosphonates. METHOD AND MATERIALS: A systematic review of the literature was performed by searching PubMed and Embase databases using MeSH terms (fibrous dysplasia of bone, "fibrous dysplasia, polyostotic," osteonecrosis, jaw, therapeutics, diphosphonates, denosumab, teriparatide, estrogens, hormones, raloxifene hydrochloride, calcitonin, cathepsin K) and non-MeSH terms (antiresorptive therapy, antiresorptives, bisphosphonate, estrogen therapy, hormone therapy, bazedoxifene, cathepsin K inhibitor). Articles were limited to human studies, in English language, in which patients were on antiresorptives for at least 1 year. PRISMA statement guidelines were used to eliminate non-relevant studies. The PICOT question asked was, "Does exposure to bisphosphonates and other antiresorptives cause occurrence of MRONJ in fibrous dysplasia and fibrous dysplasia/McCune-Albright syndrome patients followed up for at least 1 year?" RESULTS: Eight eligible articles were included in the quantitative synthesis after articles were screened using a PRISMA flowchart. There were 12 reported occurrences of MRONJ among a combined total of 312 fibrous dysplasia and fibrous dysplasia/McCune-Albright syndrome patients (3.85%). CONCLUSION: Patients with fibrous dysplasia or fibrous dysplasia/McCune-Albright syndrome have a low incidence of MRONJ and may apparently have low susceptibility to spontaneous development of MRONJ.

Neuropathic-like Pain in Fibrous Dysplasia/McCune-Albright Syndrome.

CONTEXT: Pain is a major symptom in adults with fibrous dysplasia/McCune-Albright syndrome (FD/MAS) and response to current treatments, including bisphosphonates and standard analgesics (nonsteroidal anti-inflammatory drugs and opiates) is unpredictable. No studies have explored whether the type of pain is variable in this patient group. OBJECTIVE: To determine the frequency of neuropathic-like pain in patients with FD/MAS. DESIGN: Retrospective, dual registry study. SETTING: Community. PATIENTS: FD/MAS online registries: the US-based Familial Dysautonomia Foundation (FDF) and the UK-based Rare and Undiagnosed Diseases (RUDY) study. INTERVENTION: Subjects completed questionnaires to evaluate the presence of features of neuropathic-like pain (painDETECT) and the impact on sleep quality (Pittsburgh Sleep Quality Index) and mental health (Hospital Anxiety and Depression Scale). Descriptive statistics were used to characterize the prevalence and associated burden of neuropathic-like pain. MAIN OUTCOME MEASURES: Incidence of neuropathic, nociceptive, and unclear pain. RESULTS: Of 249 participants, one third experienced neuropathic-like pain. This group had statistically significantly (P < 0.001) worse mental well-being and sleep in comparison to those with predominately nociceptive pain. CONCLUSIONS: Neuropathic-like pain is common in patients with FD/MAS and associated with worse quality of life. Evaluation of pain in patients with FD/MAS should include assessment of neuropathic-like pain to guide personalized approaches to treatment and inform future research.

Long Bone Fractures in Fibrous Dysplasia/McCune-Albright Syndrome: Prevalence, Natural History, and Risk Factors.

Fibrous dysplasia/McCune-Albright syndrome (FD/MAS) is a rare bone and endocrine disorder arising along a broad spectrum. Long-bone fractures are a common, painful, and potentially disabling complication. However, fracture prevalence and risk factors have not been well-established, making it difficult to predict which patients are at risk for a severe course. Clinical and imaging data were reviewed from two large, well-phenotyped cohorts (National Institutes of Health [NIH] in the United States and the Leiden University Medical Center [LUMC] in the Netherlands) to identify long-bone fractures at FD sites. Skeletal burden score was quantified using bone scintigraphy. Multiple linear regressions were performed to identify clinical associations with fractures. A total of 419 patients were included (186 NIH, 233 LUMC); 194 (46%) had MAS endocrinopathies. Median age at last follow-up was 30.2 years (range 3.2-84.6, interquartile range [IQR] 25.5), and median skeletal burden score was 16.6 (range 0-75, IQR 33). A total of 48 (59%) patients suffered one or more lifetime fracture (median 1, range 0-70, IQR 4). Median age at first fracture was 8 years (range 1-76, IQR 10). Fracture rates peaked between 6 and 10 years of age and decreased thereafter. Lifetime fracture rate was associated with skeletal burden score (ß = 0.40, p < 0.01) and MAS hyperthyroidism (ß = 0.22, p = 0.01). Younger age at first fracture was associated with skeletal burden score (ß = -0.26, p = 0.01) and male sex (ß = -0.23, p = 0.01). Both skeletal burden score >25 and age at first fracture ≤7 years were associated with a higher total number of lifetime fractures (median 4, range 1-70, IQR 5 versus median 1, range 1-13, IQR 1) (p < 0.01). In conclusion, higher skeletal burden score and MAS hyperthyroidism are associated with long-bone fractures in FD/MAS. Both skeletal burden score ≥25 and age at first fracture ≤7 years are associated with a higher lifetime long-bone fracture risk and may predict a more severe clinical course. These results may allow clinicians to identify FD/MAS patients at risk for severe disease who may be candidates for early therapeutic interventions. © 2021 American Society for Bone and Mineral Research (ASBMR). This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Prevalence of Polycystic Ovary Syndrome in Patients With McCune Albright Syndrome.

STUDY OBJECTIVE: To identify polycystic ovarian syndrome (PCOS) in a population of female patients with McCune-Albright syndrome (MAS) by retrospective chart review. DESIGN: Retrospective study. SETTING: Academic setting. PARTICIPANTS: All female patients with a prior diagnosis of MAS who were more than 12 years of age at the time of chart review. Only complete medical records from January 2009 to January 2020 were included in the analysis. INTERVENTIONS: None. MAIN OUTCOME MEASURE(S): Diagnosis of PCOS based on the Rotterdam 2003 criteria. RESULTS: Seventeen female patients with MAS were included in the analysis. PCOS appeared to be more prevalent in MAS patients than expected based on population estimates (exact binomial test = 0.353; CI = 0.142-0.617, P = .01). The average body mass index was not significantly different between MAS patients with and without PCOS (23.38 kg/m2 vs 23.44 kg/m2, 2-sample Wilcoxon rank-sum test with continuity correction, W = 29, P = 0.733). The majority of patients (71%) were treated with an aromatase inhibitor and/or a gonadotropin-releasing hormone (GnRH) agonist. CONCLUSIONS: The results of this study suggest that female individuals with MAS have a statistically higher prevalence of PCOS. These findings warrant further studies to determine whether the increased risk of PCOS may be associated with precocious puberty, treatment of precocious puberty, or other factors.

Genotype-Phenotype Correlation in Fibrous Dysplasia/McCune-Albright Syndrome.

CONTEXT: Fibrous dysplasia/McCune-Albright syndrome (FD/MAS) is a rare bone and endocrine disorder resulting in fractures, pain, and disability. There are no targeted or effective therapies to alter the disease course. Disease arises from somatic gain-of-function variants at the R201 codon in GNAS, replacing arginine by either cysteine or histidine. The relative pathogenicity of these variants is not fully understood. OBJECTIVE: This work aimed 1) to determine whether the most common GNAS variants (R201C and R201H) are associated with a specific clinical phenotype, and 2) to determine the prevalence of the most common GNAS variants in a large patient cohort. METHODS: This retrospective cross-sectional analysis measured the correlation between genotype and phenotype characterized by clinical, biochemical, and radiographic data. RESULTS: Sixty-one individuals were genotyped using DNA extracted from tissue or circulating cell-free DNA. Twenty-two patients (36.1%) had the R201C variant, and 39 (63.9%) had the R201H variant. FD skeletal disease burden, hypophosphatemia prevalence, fracture incidence, and ambulation status were similar between the 2 groups. There was no difference in the prevalence of endocrinopathies, ultrasonographic gonadal or thyroid abnormalities, or pancreatic involvement. There was a nonsignificant association of cancer with the R201H variant. CONCLUSION: There is no clear genotype-phenotype correlation in patients with the most common FD/MAS pathogenic variants. The predominance of the R201H variant observed in our cohort and reported in the literature indicates it is likely responsible for a larger burden of disease in the overall population of patients with FD/MAS, which may have important implications for the future development of targeted therapies.

Increased Prevalence of Malignancies in Fibrous Dysplasia/McCune-Albright Syndrome (FD/MAS): Data from a National Referral Center and the Dutch National Pathology Registry (PALGA).

Malignant transformation of fibrous dysplasia lesions has been reported in patients with fibrous dysplasia/McCune-Albright syndrome (FD/MAS). Recently, we have observed an increased risk for breast cancer. In this study, the prevalence of skeletal and extraskeletal malignancies in patients with FD/MAS in the Netherlands was assessed by analyzing data from our cohort of FD/MAS patients, the Dutch Pathology Registry (PALGA), and the Netherlands Cancer Registry (NCR). We extracted data on sex, age at diagnosis of FD/MAS, type of FD/MAS, type of malignancy, and age at diagnosis of malignancy and histology of bone and malignant tissue when available, including GNAS-mutation analysis from patients' medical records. Standardized Morbidity Ratios (SMRs) with 95% confidence intervals were calculated. Twelve malignancies were identified in the LUMC FD/MAS cohort and 100 in the PALGA cohort. In this cohort, SMR was increased for osteosarcoma (19.7, 95% CI 3.5-48.9), cervical cancer (4.93, 95%CI 1.7-8.2), thyroid cancer (3.71, 95% CI 1.1-7.8), prostate cancer (3.08, 95% CI 1.8-4.6), and melanoma (2.01, 95%CI 1.2-3.1). SMRs for pancreatic cancer or hepatocellular carcinoma could not be calculated due to low numbers. The small number of malignancies identified in our FD/MAS cohort precluded the calculation of SMRs for our cohort specifically. Our findings show that patients with FD/MAS appear to have an increased risk for osteosarcoma, cervical, thyroid, and prostate cancer and melanoma. However, these data should be interpreted with caution, as true incidence rates of the identified malignancies may be influenced by the inclusion of only patients with histologically confirmed FD/MAS. The etiology of this increased risk for malignancies still needs to be elucidated.

Natural History and Progression of Craniofacial Fibrous Dysplasia: A Retrospective Evaluation of 114 Patients From Massachusetts General Hospital.

PURPOSE: The natural history of fibrous dysplasia (FD) is poorly understood. The purpose of this study was to identify differences in demographic, clinical, and radiographic characteristics among patients with craniofacial FD, including McCune-Albright syndrome (MAS), polyostotic fibrous dysplasia (PFD), and monostotic fibrous dysplasia (MFD). We hypothesized that patients with MAS would show higher disease severity, have more complications, and undergo more operations than those with PFD or MFD. PATIENTS AND METHODS: A retrospective cohort study of patients with MAS or FD, evaluated at Massachusetts General Hospital from 2000 to 2018, was implemented. Patients of all ages and genders were identified through Massachusetts General Hospital Data Registries using International Classification of Diseases, Ninth Revision (ICD-9) and International Classification of Diseases, Tenth Revision (ICD-10) codes. Those with adequate clinical and radiographic data were included. Predictor variables were diagnosis of MAS, PFD, or MFD; age; and gender. Outcome variables included severity of disease at initial presentation (aggressive, nonaggressive and slow growing, or quiescent), number of operations, and complications: pain, sensory disturbances, pathologic fracture, airway obstruction, osteomyelitis, and dental findings. Data were analyzed with descriptive statistics and assessed for significance using χ2 tests and analysis of variance (P < .05). RESULTS: A total of 229 patients were identified: 114 had craniofacial FD, and 70 of these 114 (61.4%) met the inclusion criteria (48 of whom were female patients). The average age at diagnosis was 23.5 years; mean length of follow-up, 5.8 years. Diagnoses included MAS in 9 patients, PFD in 24, and MFD in 37. Signs and symptoms at initial presentation were pain (n = 29), sensory abnormalities (n = 13), facial deformity or swelling (n = 54), and dental findings (n = 25). At presentation, the biological behavior of disease was 77.8% aggressive, 11.1% nonaggressive, and 11.1% quiescent in the MAS group; 41.7%, 41.7%, and 16.7%, respectively, in the PFD group; and 29.7%, 29.7%, and 40.5%, respectively, in the MFD group. Patients with MAS were younger and were more likely to have pain, pathologic fractures, more bones involved, bilateral disease, and visual symptoms than those with PFD or MFD. MAS patients underwent more operations (mean, 4.2 ± 4.18) than those with PFD (mean, 2.6 ± 2.31; P = not significant) or MFD (mean, 1.7 ± 1.28; P = .010). CONCLUSIONS: The results of this study indicate that patients with MAS, presumably with the same mutation, are more likely to have aggressive disease, complications, and more operations than those with PFD or MFD.

Denosumab in Patients With Fibrous Dysplasia Previously Treated With Bisphosphonates.

CONTEXT: Fibrous dysplasia/McCune-Albright syndrome (FD/MAS) is a rare bone disorder commonly treated with bisphosphonates, but clinical and biochemical responses may be incomplete. OBJECTIVE: To evaluate the efficacy and tolerability of the receptor activator of nuclear factor-κB ligand inhibitor denosumab in the treatment of patients with FD/MAS refractory to bisphosphonate therapy. DESIGN: Case series. SETTING: Academic center of expertise for rare bone diseases. PATIENTS: Data were collected from 12 consecutive patients with FD/MAS with persistent pain and increased biochemical markers of bone turnover (BTMs) after long-term treatment with bisphosphonates (median, 8.8 years) and were treated with subcutaneous denosumab 60 mg at 3- or 6-month intervals with a follow-up for at least 12 months. MAIN OUTCOME(S): Sustained reduction of BTMs and bone pain. RESULTS: A 60 mg dose of denosumab once every 3 months, but not once every 6 months, induced a sustained reduction of BTMs. After a median treatment period of 15.5 months (range, 12 to 19) serum alkaline phosphatase activity and propeptide of type 1 procollagen levels were respectively reduced from 212 ± 39.4 IU/L to 79 ± 6.0 IU/L (P = 0.004) and from 346.2 ± 111.1 ng/mL to 55.7 ± 16.6 ng/mL (P = 0.023) and normalized in 70% and 75% of patients, respectively. Although not quantitavely measured, 10 patients reported a reduction in bone pain of whom 6 reported complete elimination of pain. Treatment with denosumab was well tolerated. CONCLUSION: Our results indicate that 60 mg of denosumab every 3 months is a promising, well-tolerated treatment of most patients with FD/MAS refractory to bisphosphonate therapy. These results together with those of previously published case reports provide the necessary background for the design of a larger, controlled study.

Prevalence and Clinical Features of Mazabraud Syndrome: A Multicenter European Study.

BACKGROUND: Mazabraud syndrome is a rare disorder, characterized by the presence of fibrous dysplasia (FD) with associated intramuscular myxomas. Data are scarce on the prevalence, clinical features, and natural history of this disorder and outcomes. In this multicenter study, we evaluated a series of patients from 6 European centers. METHODS: All centers affiliated with the European Musculo-Skeletal Oncology Society (EMSOS) were invited to include data on all patients with Mazabraud syndrome who were seen between 1980 and 2015. The study investigated the prevalence of Mazabraud syndrome, the type, severity, and localization of FD lesions in relation to myxomas, the histopathology of myxomas, and results of GNAS-mutation analysis, when available. RESULTS: Thirty-two patients (22 female) from 6 centers were included. The prevalence of Mazabraud syndrome was 2.2% in the combined cohort of 1,446 patients with FD, and the syndrome was diagnosed at a mean of 10.1 years after diagnosis of FD. The myxomas were predominantly localized in the upper leg. Excision was performed in 20 patients, recurrence occurred in 6 of these patients (30%) at a median of 8.5 years (range, 1.9 to 16.0 years), and revision surgery was necessary in 5 (25%). High cellularity of myxomas was associated with recurrence (p < 0.05). A GNAS mutation was identified in the myxoma tissue of 5 (83%) of 6 patients with GNAS-mutation analysis. CONCLUSIONS: This study is the first, to our knowledge, to provide data on the prevalence of Mazabraud syndrome in a relatively large cohort. Although the outcomes of surgical resection were good, a quarter of the patients required revision surgery despite clear resection margins. High cellularity of myxomas was associated with recurrence. GNAS mutations were identified in 83% (5 of 6), emphasizing the shared origin of FD and myxomas. Our data show that patients with FD who have disproportionate complaints, irrespective of FD type, extent, or severity, should be investigated for the possible presence of myxomas. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Improving patient outcomes in fibrous dysplasia/McCune-Albright syndrome: an international multidisciplinary workshop to inform an international partnership.

To develop consensus on improving the management of patients, we convened an international workshop involving patients, clinicians, and researchers. Key findings included the diagnostic delay and variability in subsequent management with agreement to develop an international natural history study. We now invite other stakeholders to join the partnership. PURPOSE: The aim of this study was develop a consensus on how to improve the management of patients with fibrous dysplasia and prioritize areas for research METHODS: An international workshop was held over 3 days involving patients, clinicians, and researchers. Each day had a combination of formal presentations and facilitated discussions that focused on clinical pathways and research. RESULTS: The patient workshop day highlighted the variability of patients' experience in getting a diagnosis, the knowledge of general clinical staff, and understanding long-term outcomes. The research workshop prioritized collaborations that improved understanding of the contemporary natural history of fibrous dysplasia/McCune-Albright syndrome (FD/MAS). The clinical workshop outlined the key issues around diagnostics, assessment of severity, treatment and monitoring of patients. CONCLUSIONS: In spite of advances in understanding the genetic and molecular underpinnings of fibrous dysplasia/McCune-Albright syndrome, clinical management remains a challenge. From the workshop, a consensus was reached to create an international, multi-stakeholder partnership to advance research and clinical care in FD/MAS. We invite other stakeholders to join the partnership.

Prevalence of Different Forms and Involved Bones of Craniofacial Fibrous Dysplasia.

BACKGROUND: The purposes of this study were to analyze the prevalence of various craniofacial bones involved in patients with craniofacial fibrous dysplasia (CFD) and to demonstrate the most common form and bone involvement in patients with CFD for surgeons. METHODS: To address the research purpose, the authors designed and performed a systematic review with meta-analysis. A comprehensive electronic search without date was performed in August 2013. Data extracted from the previously published literature were analyzed with STATA 11.0 software. RESULTS: Relevant data were extracted from 18 studies (487 total participants) and revealed that in CFD patients, the prevalence of the monostotic type was 56% (95% confidence intervals [CI]: 0.42-0.70; P = 0.000) and polyostotic type was 47% (95% CI: 0.31-0.63; P = 0.000); McCune-Albright syndrome was a relatively rare form (7%; 95% CI: 0.02-0.12; P = 0.006). Subgroup analyses indicated that the maxilla was most commonly involved (28%; 95% CI: 0.42-0.70; P = 0.000) in monostotic CFD, followed by the orbital (27%; 95% CI: -0.23-0.76; P = 0.298), mandibular (25%; 95% CI: 0.16-0.35; P = 0.000), frontal (22%; 95% CI: 0.09-0.34; P = 0.001), and temporal bones (12%; 95% CI: 0.03-0.21; P = 0.012). The prevalence of maxilla involvement in polyostotic CFD patients was as high as 30% (95% CI: 0.18-0.42; P = 0.000). CONCLUSION: This meta-analysis found that monostotic and polyostotic forms of CFD shared similar prevalence rates. Furthermore, the maxilla was found to be the most commonly involved bone in both monostotic and polyostotic CFD.

Clinical and endocrine characteristics and genetic analysis of Korean children with McCune-Albright syndrome: a retrospective cohort study.

BACKGROUND: McCune-Albright syndrome (MAS) is a rare disease defined by the triad of fibrous dysplasia (FD), café au lait spots, and peripheral precocious puberty (PP). Because of the rarity of this disease, only a few individuals with MAS have been reported in Korea. We describe the various clinical and endocrine manifestations and genetic analysis of 14 patients with MAS in Korea. METHODS: Patients' clinical data-including peripheral PP, FD, and other endocrine problems-were reviewed retrospectively. In addition, treatment experiences of letrozole in five patients with peripheral PP were described. Mutant enrichment with 3'-modified oligonucleotides - polymerase chain reaction (MEMO-PCR) was performed on eight patients to detect mutation in GNAS using blood. MEMO-PCR is a simple and practical method that enables the nondestructive selection and enrichment of minor mutant alleles in blood. RESULTS: The median age at diagnosis was 5 years 2 months (range: 18 months to 16 years). Eleven patients were female, and three were male. Thirteen patients showed FD. All female patients showed peripheral PP at onset, and three patients subsequently developed central PP. There was a significant decrease in estradiol levels after two years of letrozole treatment. However, bone age was advanced in four patients. Two patients had clinical hyperthyroidism, and two patients had growth hormone (GH) excess with pituitary microadenoma. c.602G > A (p.Arg201His) in GNAS was detected in two patients in blood, and c.601C > T (p.Arg201Cys) in GNAS was detected in one patient in pituitary adenoma. CONCLUSIONS: This study described the various clinical manifestations of 14 patients with MAS in a single center in Korea. This study first applied MEMO-PCR on MAS patients to detect GNAS mutation. Because a broad spectrum of endocrine manifestations could be found in MAS, multiple endocrinopathies should be monitored in MAS patients. Better treatment options for peripheral PP with MAS are needed.

Prognostic Factors From an Epidemiologic Evaluation of Fibrous Dysplasia of Bone in a Modern Cohort: The FRANCEDYS Study.

Fibrous dysplasia of bone (FD) is a rare genetic but sporadic bone disease that can be responsible for bone pain, fracture, and bone deformity. The prognosis may be difficult to establish because of the wide spectrum of disease severity. We have analyzed the data from the French National Reference center for FD. We have established a database from standardized medical records. We have made descriptive statistics of the various forms of FD and examined the prognostic factors by multivariable logistic regression analysis, with a parsimonious stepwise method. The primary outcome was a clinically relevant composite index combining bone pain (visual analogic scale >3) and/or incident fracture. In our modern cohort of 372 patients, the median age at diagnosis was 23 years. The revealing symptom (at a median age of 18 years) was bone pain in 44% of patients and a fracture in 9%, but the diagnosis was fortuitous in 25% of cases. Monostotic forms represented 58% of patients and polyostotic forms 42%. The femur was the most commonly affected bone (44% of patients), followed by the skull (38%). Twelve percent of patients had McCune-Albright syndrome (MAS). With a median duration of follow-up of 7 years among 211 patients, we observed an incidence of fracture of 17% and 51% of patients had no bone pain at the end of follow-up (with or without bisphosphonate therapy). In univariate analysis, younger age at diagnosis, renal phosphate wasting, a polyostotic form, prevalent fracture, and bisphosphonate use were significant predictors. In the multivariate model, the polyostotic form and bisphosphonate use remained significant predictors. In conclusion, in a national referral center for FD, one patient on follow-up out of six had incident fracture. A polyostotic form was the main risk factor of a poorer outcome. © 2016 American Society for Bone and Mineral Research.

Internal fixation after fracture or osteotomy of the femur in young children with polyostotic fibrous dysplasia.

Children from 4 to 7 years of age with polyostotic fibrous dysplasia (PFD) may need internal fixation of the femur for either fracture or osteotomy. At that age, the small size of the femur allows only the use of small intramedullary nails. However, titanium elastic nails and rigid intramedullary pediatric interlocking femoral nails - good for fracture or osteotomy fixation in the normal femur - are not indicated in PFD. From 2009 to 2011, we treated eight cases of PFD femoral fracture and deformity by internal fixation with a custom-modified adult humeral nail to which a spiral blade was connected. The 7-mm thick nail fit properly into the small femoral shaft and the spiral blade conferred ideal mechanical support to the femoral neck. Three cases had replacement of the humeral nail with a more appropriate adult femoral nail 3 years after the index procedure when the femur had reached an adequate size. In the maximum follow-up period of 4 years, few complications were observed.

Acromegaly and McCune-Albright syndrome.

BACKGROUND: McCune-Albright syndrome (MAS) includes the triad of poly/monostotic fibrous dysplasia, café-au-lait spots, and hyperfunctioning endocrinopathies. Acromegaly affects around 20% of MAS patients. AIMS: The objective was to review all reported cases of acromegaly associated with MAS. METHODS: All studies and case reports of acromegaly in patients with MAS were systematically sought in the world literature up to January 2013. We also included new data (from three unreported cases) and updated data on 23 previously reported patients from our two centers. RESULTS: We reviewed the cases of 112 patients (65 males). Mean age at diagnosis of acromegaly was 24.4 years (range, 3-64). Among the 40 pediatric patients, 23 (57%) had precocious puberty. GH/IGF-1 excess was suggested by accelerated growth in 85% of pediatric cases. Acromegaly was almost always associated with skull base fibrous dysplasia. Modern imaging techniques (computed tomography or magnetic resonance imaging) revealed an adenoma in 54% of the patients (macroadenoma in more than two-thirds). Median GH levels and mean IGF-1 SD score at diagnosis were 57 µg/L (2.8 to 291 µg/L) and 8 (2.3 to 24), respectively. Hyperprolactinemia was present in 81% (mean, 149 µg/L; range, 21-600). Pituitary surgery, performed in 25 cases, very rarely cured the GH/IGF-1 excess. Somatostatin analogs improved GH/IGF-1 levels in most patients but achieved control of acromegaly in only 17 (30%) of 56 patients. Pegvisomant achieved normal IGF-1 levels in 10 of 13 cases. CONCLUSION: Acromegaly, which is present in 20-30% of patients with MAS, raises particular diagnostic and therapeutic issues.

Surgical treatment of craniofacial fibrous dysplasia in adults.

Craniofacial fibrous dysplasia (FD) is a rare disorder that may require neurosurgical expertise for definitive management; however, surgical management of FD in adult patients is uncommon. Although other therapies have been shown to slow progression, the only definitive cure for adult craniofacial FD is complete resection with subsequent reconstruction. The authors review the biological, epidemiologic, clinical, genetic, and radiographic characteristics of adult FD, with an emphasis on surgical management of FD. They present a small series of three adult patients with complex FD that highlights the surgical complexity required in some adult patients with FD. Because of the complex nature of these adult polyostotic craniofacial cases, the authors used neurosurgical techniques specific to the different surgical indications, including a transsphenoidal approach for resection of sphenoidal sinus FD, a transmaxillary approach to decompress the maxillary branch of the trigeminal nerve with widening of the foramen rotundum, and complete calvarial craniectomy with cranioplasty reconstruction. These cases exemplify the diverse range of skull base techniques required in the spectrum of surgical management of adult FD and demonstrate that novel variations on standard neurosurgical approaches to the skull base can provide successful outcomes with minimal complications in adults with complex craniofacial FD.

Hepatobiliary and Pancreatic neoplasms in patients with McCune-Albright syndrome.

BACKGROUND: McCune-Albright syndrome (MAS), which includes polycystic fibrous dysplasia, precocious puberty, and café au lait spots, is a rare disorder caused by somatic activating mutations of the GNAS gene. GNAS mutations have also been implicated in various sporadic tumors, including hepatobiliary and pancreatic neoplasms. AIM: The aim of this study was to assess the prevalence of hepatobiliary and pancreatic neoplasms in patients with McCune-Albright syndrome. PATIENTS AND METHODS: Nineteen patients diagnosed between 1995 and 2012 with MAS in a tertiary referral center for rare growth disorders were screened with dedicated gadolinium-enhanced magnetic resonance imaging for hepatobiliary and pancreatic neoplasms between June 2011 and December 2012. RESULTS: Six (32%) of the 19 screened patients were found to have hepatic, pancreatic, or biliary lesions, excluding liver hemangiomas, liver cysts, and focal nodular hyperplasia. This includes pancreatic ductal lesions observed in 4 patients, including numerous branch-duct intraductal papillary mucinous neoplasms in 3 patients. Biliary lesions were observed in 1 patient, with a large choledochal cyst also involving the left biliary branch. Finally, multiple inflammatory/telangiectatic hepatic adenomas were observed in 2 patients, including 1 with proven somatic GNAS mutation. CONCLUSION: We describe the first observation of syndromic intraductal papillary mucinous neoplasms and the new association between MAS and pancreatic neoplasms, namely intraductal papillary mucinous neoplasms of the pancreas but also rare hepatobiliary neoplasms including liver adenomas and choledochal cysts. These findings strongly suggest that somatic activating GNAS mutations, possibly through cAMP pathway disorders, are involved in the tumorigenesis of hepatobiliary and pancreatic tissues originating from the foregut endoderm and have led us to use a routine screening by dedicated magnetic resonance imaging including both pancreatobiliary and liver sequences in patients with MAS.