Fibrous dysplasia. Pathophysiology, evaluation, and treatment

Fibrous dysplasia of the head and neck in Southern Finland: a retrospective study on clinical characteristics, diagnostics, and treatment

PURPOSE

Fibrous dysplasia (FD) is a rare genetic disease with benign bone tumors. FD can affect one (monostotic FD) or multiple bones (polyostotic FD), with craniofacial lesions being common. Because of its rarity, there are only few clinical reports on FD in the head and neck region and its clinical characteristics remain incompletely defined. This study aimed to determine patient demographics, symptoms, diagnostics, and given treatment in patients with FD of the head and neck in a Finnish population.

METHODS

A retrospective review on all patients diagnosed with or treated for FD of the head and neck at the Helsinki University Hospital during 2005-2020.

RESULTS

In total 74 patients were identified; 54% were male and the mean age 45 years. Overall 95% had monostotic FD. Mandibula and maxilla were the most common anatomic sites. Majority of patients had symptoms, most commonly pain and lesion growth, and 49% had extra-skeletal symptoms. For all, diagnosis was primarily based on imaging findings, biopsies were obtained from 41%. Altogether 54 patients (73%) were managed by observation only, 20 patients (27%) received treatment; ten bisphosphonates, six surgery and four both.

CONCLUSION

Although highly variable in its clinical manifestations, head and neck FD lesions are often symptomatic and impose risk for extra-skeletal complications. Treatment is often conservative but should be individually tailored. Future studies are encouraged to better define the disease characteristics and hopefully offer new treatment possibilities.

Whole Exome Sequencing as an Effective Molecular Diagnosis Tool for Craniofacial Fibrous Dysplasia with Ocular Complications

PURPOSE

To summarize the clinical manifestations of craniofacial fibrous dysplasia (CFD) patients with ocular complications, and find effective methods to diagnose early.

METHODS

Nine CFD patients with ocular complications, and their parents were recruited in this study. All patients underwent ocular and systemic examinations. Bone lesions from all patients and peripheral blood from patients and their parents were collected for whole exome sequencing (WES). According to the screening for low-frequency deleterious variants, and bioinformatics variants prediction software, possible disease-causing variants were found in multiple CFD patients. The variants were validated by Sanger sequencing. Trio analysis was performed to verify the genetic patterns of CFD.

RESULTS

All patients were diagnosed with CFD, according to the clinical manifestations, classic radiographic appearance, and pathological biopsy. The main symptoms of the 9 CFD patients, included visual decline (9/9), craniofacial deformity (3/9) and strabismus (2/9), with few extraocular manifestations. The family backgrounds of all the CFD patients indicated that only the patient was affected, and their immediate family members were normal. GNAS variants were identified in all bone lesions from CFD patients, including two variant types: c.601C > T:p.R201C(6/9) and c.602G > A:p.R201H (3/9) in exon 8. The detection rate reached 100% by WES, but only 77.8% by Sanger sequencing. Interestingly, we found GNAS variants could not be detected in peripheral blood samples from CFD patients or their parents, and other potentially disease-causing gene variants related to CFD were not found.

CONCLUSIONS

For CFD patients with bone lesions involving the optic canal or sphenoid sinus regions, ocular symptoms should also be considered. Furthermore, we confirmed that CFD is not inherited, somatic variants in the GNAS gene are the main pathogenic gene causing CFD. Compared to the traditional methods in molecular genetic diagnosis of CFD, WES is more feasible and effective but limited in the type of samples.

Diagnosis and Management of Monostotic Fibrous Dysplasia of the Tibia in an Adolescent Patient: A Case Report

A rare benign bone condition called monostotic fibrous dysplasia (MFD) is characterized by the growth of fibrous tissue in place of a normal bone. It may lead to deformity in the affected bone, pain, and a pathologic fracture due to bone weakness. Hereunder, a case report of MFD in a 17-year-old male adolescent presenting to the hospital with localized bone pain and swelling in his right tibia is presented. After clinical examination and radiographic imaging, a provisional diagnosis of benign osteolytic lesion was considered. A magnetic resonance imaging (MRI) scan of the leg suggested the possibility of fibrous dysplasia or adamantinoma. The patient was managed with an intralesional curettage of the dysplastic bone and packing the cavity with blocks of a synthetic bone. The excised material was sent for histopathology, which established the diagnosis of fibrous dysplasia.

A Case Series and Literature Review of Craniofacial Fibrous Dysplasia

Craniofacial fibro-osseous lesions (CFOLs) are a diverse group of relatively rare entities whose etiology ranges from reactive to dysplastic with a potential for malignant transformation. It is distinguished by the replacement of bone with fibrous tissue, that subsequently develops different degrees of calcification. Fibrous dysplasia (FD) is a component of the fibro-osseous lesion spectrum. The clinical spectrum of FD is wide, ranging from minor monostotic lesions affecting a single bone to devastating polyostotic disease involving the entire skeleton. FD produces asymmetry, which impairs face aesthetics. FD leads to bone differentiation, disintegration, and disorganization. It depicts a cellular collagenous stroma lacking mitotic figures and pleomorphism. Blood capillaries are evenly distributed, as are elongated trabeculae of woven or lamellar bone with uneven curves (often referred to as the Chinese letters pattern). Three types of FD patterns can be identified by computed tomography (CT) imaging: a cystic pattern, a homogeneously dense pattern, and a ground-glass pattern. The cornerstone of treatment is surgery, although the method varies depending on the location, size, and symptoms of the lesion. As an alternative to surgery, the use of bisphosphonates to reduce osteoclastic activity is under consideration. In this case series, we present three cases of FD involving the maxilla and mandible. We aim to correlate the clinical presentation, histological features, and radiographic findings, to promote early diagnosis, treatment, and better prognosis of the patient.

A Rare Case of Monostotic Fibrous Dysplasia of the Femoral Neck With Pathological Fracture: A Case Report

Fibrous dysplasia is a rare benign bone disorder characterized by the replacement of normal bone with fibroblastic and osteoblastic tissue. We present a case of monostotic fibrous dysplasia in a 25-year-old male patient. The case highlights the clinical presentation, radiographic features, and management approach for this condition. This report aims to contribute to the understanding of fibrous dysplasia and its management options. A 25-year-old male presented with a chief complaint of persistent left hip pain. The pain was described as a dull ache, associated with difficulty in weight-bearing activities. There was no history of trauma or constitutional symptoms. Physical examination revealed externally rotated left lower limb. Range of motion of the left hip could not be assessed due to pain, with no neurological deficits noted. Initial imaging included plain radiographs of the right femur, which demonstrated a radiolucent lesion with a ground-glass appearance and cortical thinning. Magnetic resonance imaging of both hip joints reveals an irregular T2 hyperintense and T1 hypointense lesion involving the left femoral neck; moreover, few tiny cystic spaces are seen within the lesion. Part of the lesion is extending into the superior-lateral aspect of the femoral head and surrounding bone marrow edema with minimal left hip joint effusion, features suggestive of a primary bony tumour. Plain computed tomography (CT) of the hip joint and pelvis was suggestive of an expansile lytic lesion with thin bony septation within and thick sclerotic margin in the left femoral head and greater trochanter associated with sub-capital femoral neck fracture suggestive of bone neoplasm (? giant cell tumour > simple bone cyst). A bone biopsy was performed, and histopathological examination confirmed the diagnosis of fibrous dysplasia, with characteristic woven bone and fibrous stroma. In this case, after confirming the diagnosis, the patient was managed with total hip arthroplasty on the left side. Monostotic fibrous dysplasia is a rare benign bone disorder that can present with various clinical manifestations. Timely diagnosis through a combination of clinical, radiographic, and histopathological assessments is crucial. Management should be tailored to the patient's symptoms.

GNAS locus: bone related diseases and mouse models

GNASis a complex locus characterized by multiple transcripts and an imprinting effect. It orchestrates a variety of physiological processes via numerous signaling pathways. Human diseases associated with the GNAS gene encompass fibrous dysplasia (FD), Albright's Hereditary Osteodystrophy (AHO), parathyroid hormone(PTH) resistance, and Progressive Osseous Heteroplasia (POH), among others. To facilitate the study of the GNAS locus and its associated diseases, researchers have developed a range of mouse models. In this review, we will systematically explore the GNAS locus, its related signaling pathways, the bone diseases associated with it, and the mouse models pertinent to these bone diseases.

Aneurysmal bone cyst arising from the surgically removed craniofacial fibrous dysplasia in the long-term follow-up: a case report

Fibrous dysplasia (FD) is a rare skeletal disorder characterized by abnormal fibro-osseous connective tissue replacing normal bone. Despite its benign behavior, craniofacial FD can cause morphological disfigurement, headache, and even blindness as a result of the produced mass effect. Surgical resection is recommended when the patient shows apparent clinical symptoms or aggravating facial asymmetry. Postoperative complications have been reported, such as hematoma, surgical site infection, abscess formation, resorption of the bone graft used for reconstruction, and recurrence. An aneurysmal bone cyst (ABC) is a rare benign bony lesion that can occur secondary to preexisting bone tumor. Secondary ABCs in craniofacial FD are extremely rare in the literature, accounting for less than 30, all of which are either case reports or series. We report an extremely rare case of symptomatic secondary ABC arising from craniofacial FD that had been misdiagnosed with abscess formation or recurrence and was surgically removed. Notably, 17 years elapsed between the primary surgery and the complication of secondary ABC. The patient underwent total removal of secondary ABC. After surgery, symptoms were relieved, with no recurrence observed during a 6-month follow-up.

Multimodal imaging diagnosis for bone fibrous dysplasia malignant transformation: A case report

Fibrous dysplasia of bone (FDB) is a rare benign condition in which fibrous tissue replaces normal bone architecture. FDB rarely undergoes malignant transformation, but there are reports of locally aggressive fibrous dysplasia with cortical destruction and soft tissue extension. Diagnosis of FDB malignant transformation is not easy, especially in monostotic form, because of the overlap in imaging features of locally aggressive fibrous dysplasia and fibrous dysplasia with malignant transformation. The present case study reports a rare case of FDB in a 23-year-old man with polyostotic fibrous dysplasia arising in the left side of the pelvis and lower limb bones with partial transformation to fibrosarcoma. This study explored the multimodal imaging features of FDB malignant transformation, to achieve early detection and improve diagnostic accuracy of local FDB aggressiveness and its malignant transformation.

Fibrous Dysplasia of the Clivus: Case Report and Literature Review

Fibrous dysplasia is a benign, developmental bone disorder that causes fibrous replacement of normal skeletal tissue. This may lead to weakness, distortion, and tissue expansion. Fibrous dysplasia can occur anywhere in the body, including the craniofacial area. The clivus is a central skull bone formed by the bases of the sphenoid and occiput, respectively. The clivus is a rare, usually unrecognized, and seldom reported location for the development of fibrous dysplasia. Although fibrous dysplasia of the clivus (FDC) is usually discovered by incidental findings, it can sometimes present with clinical symptoms. In this case, we discuss a 30-year-old male who presents to the emergency room with headaches, altered mental status, and a prior presentation of location-related symptomatic epilepsy. Magnetic resonance imaging depicted a mass in the clivus, low in signal on T1 and mildly hypointense on T2 imaging. Follow-up computed tomography (CT) imaging, as recommended, revealed the classic presentation of FDC. In this paper, we discuss the significance of this condition and the importance of thorough investigation to rule out differential diagnoses that may present with similar acute symptoms as this patient.

Lower-limb intramedullary nailing in patients with polyostotic fibrous dysplasia who had a previous unsuccessful treatment. A report of 48 cases

BACKGROUND

Intramedullary nailing (IN) seems to be the best primary surgical treatment for patients with either polyostotic fibrous dysplasia or McCune-Albright syndrome (PFD/MAS) when the femur and tibia are totally affected by fibrous dysplasia (FD) and pain, fracture and deformity are likely to occur. However, other management protocols have been applied in these cases, often leading to disabling sequelae. This study sought to evaluate if IN could also have been effective as a salvage procedure to provide patients with satisfactory results, regardless of the poor results due to the improper treatment previously performed.

MATERIALS AND METHODS

Twenty-four retrospectively registered PFD/MAS patients with 34 femurs and 14 tibias totally affected by fibrous dysplasia had received various treatments with unsatisfactory results in other institutions. Before the IN performed in our hospital, 3 patients were wheelchair bound; 4 were fractured; 17 limped; and many used an aid for walking. Salvage IN was performed in our hospital at a mean patient age of 23.66 ± 6.06 years (range, 15-37 years). The patients were evaluated before-except for the four fractured ones-and after IN using the validated Jung scoring system, and the data were statistically analyzed.

RESULTS

The mean length of follow-up after IN was 9.12 ± 3.68 years (range, 4-17 years). The patients' mean Jung score significantly improved from 2.52 ± 1.74 points before IN to 6.78 ± 2.23 at follow-up (p < 0.05). Ambulation was improved in ambulatory patients and restored in wheelchair users. The complication rate was 21%.

CONCLUSIONS

Regardless of the high rate of complications, IN may be considered a reliable surgical procedure to salvage a failed treatment in PFD/MAS, with long-lasting satisfactory results achieved in most patients. Trial registration statement: Not applicable.

LEVEL OF EVIDENCE

IV.

Current concepts of craniofacial fibrous dysplasia: pathophysiology and treatment

Fibrous dysplasia is an uncommon genetic disorder in which bone is replaced by immature bone and fibrous tissue, manifesting as slowgrowing lesions. Sporadic post-zygotic activating mutations in GNAS gene result in dysregulated GαS-protein signaling and elevation of cyclic adenosine monophosphate in affected tissues. This condition has a broad clinical spectrum, ranging from insignificant solitary lesions to severe disease. The craniofacial area is the most common site of fibrous dysplasia, and nine out of 10 patients with fibrous dysplasia affecting the craniofacial bones present before the age of 5. Surgery is the mainstay of treatment, but the technique varies according to the location and severity of the lesion and associated symptoms. The timing and indications of surgery should be carefully chosen with multidisciplinary consultations and a patient-specific approach.

Pearls & Oy-sters: Sequential Bilateral Hearing and Vision Loss With Optic Disc Swelling Due to Sphenoid Bone Craniofacial Fibrous Dysplasia

Bilateral optic disc swelling is a common finding but rarely associated with multiple cranial neuropathies. In this case, an 18-year-old man presented with subacute sequential hearing loss followed by subacute sequential visual loss. Clinical examination revealed bilateral optic disc swelling. Lumbar puncture revealed a normal opening pressure of 15 cmH₂o. This case discusses a rare but important cause of bilateral optic disc swelling in the context of hearing loss, disequilibrium, and a normal CSF opening pressure. An overview of the literature is provided, and treatment options are discussed to guide further management of similar cases.

A two-generation hyperparathyroidism-jaw tumor (HPT-JT) syndrome family: clinical presentations, pathological characteristics and genetic analysis: a case report

Background

Hyperparathyroidism-Jaw Tumor (HPT-JT) is caused by inactivating germline mutations of CDC73. This hereditary disease can present with a range of symptoms. Jaw ossifying fibroma (OF) is one of the most important clinical presentations, affecting 30% of HPT-JT patients. However, OF is easily confused with other fibro-osseous lesions (FOLs) of the jaw. The correct diagnosis of HPT-JT is a real challenge and must be confirmed by genetic testing.

Case presentation

A female proband and her father suffered from multiple and recurrent FOLs in the jaw. Considering well demarcated margin and heterogeneous calcified substance lying in a variable density of fibrous stroma, we reached the diagnosis of jaw OF through radiologic and microscopic analyses. Additionally, the proband presented with chronic anemia resulting from menorrhagia, as well as renal mixed epithelial and stromal tumor (MEST). Two patients both presented with no evidence of Hyperparathyroidism (HPT). A germline start codon mutation (c.1A > G) of CDC73 was identified in them. Copy number loss at the CDC73 gene locus was verified in the jaw tumor sample of the proband.

Conclusion

Regardless of whether HPT manifestations are present, patients with heritable jaw OF may be at risk for HPT-JT. Genetic testing should be adopted to confirm the diagnosis. Early recognition of HPT-JT helps to better develop tailored treatment plans and surveillance programs.

Pediatric Benign Fibro-Osseous Lesions of the Nose and Paranasal Sinuses: A Tertiary Hospital Experience

Background

Pediatric benign fibro-osseous lesions of the nose and paranasal sinuses are considered rare neoplastic entities. These fibro-osseous lesions are difficult to accomplish owing to the multifaceted anatomy of the skull base in addition to the closeness to neurovascular configurations.

Objective

The study aimed to study different clinical presentations, radiological manifestations, surgical management, and consequences of different benign fibro-osseous lesions in the pediatric age groups. Methods and Settings. This is a case series study of a single-center experience.

Results

Four different cases were presented and discussed (osteoma, fibrous dysplasia, and ossifying fibroma.

Conclusion

We reported four different cases of osteoma, ossifying fibroma, and fibrous dysplasia. All of these cases were managed endoscopically with no postoperative complications. Endoscopic management is considered highly effective with reduced morbidity. Preoperative radiographic studies are highly essential for diagnosis and operative planning.

Expression of Beta-Catenin, Cadherins and P-Runx2 in Fibro-Osseous Lesions of the Jaw: Tissue Microarray Study

Fibrous dysplasia (FD) and hyperparathyroidism-jaw tumor syndrome (HPT-JT) are well-characterized benign bone fibro-osseous lesions. The intracellular mechanism leading to excessive deposition of fibrous tissue and alteration of differentiation processes leading to osteomalacia have not yet been fully clarified. Tissue Microarray (TMA)-based immunohistochemical expression of β-catenin, CK-AE1/AE3, Ki-67, cadherins and P-Runx2 were analyzed in archival samples from nine patients affected by FD and HPT-JT and in seven controls, with the aim of elucidating the contribution of these molecules (β-catenin, cadherins and P-Runx2) in the osteoblast differentiation pathway. β-catenin was strongly upregulated in FD, showing a hyper-cellulated pattern, while it was faintly expressed in bone tumors associated with HPT-JT. Furthermore, the loss of expression of OB-cadherin in osteoblast lineage in FD was accompanied by N-cadherin and P-cadherin upregulation (p < 0.05), while E-cadherin showed a minor role in these pathological processes. P-Runx2 showed over-expression in six out of eight cases of FD and stained moderately positive in the rimming lining osteoblasts in HPT-JT syndrome. β-catenin plays a central role in fibrous tissue proliferation and accompanies the lack of differentiation of osteoblast precursors in mature osteoblasts in FD. The study showed that the combined evaluation of the histological characteristics and the histochemical and immunohistochemical profile of key molecules involved in osteoblast differentiation are useful in the diagnosis, classification and therapeutic management of fibrous-osseous lesions.

Differential Diagnosis of Rare Diseases Involving Bilateral Lower Extremities with Similar 99mTc-MDP Bone Scan Patterns: Analysis of a Case Series

Here, we reported a panel of rare diseases involving bilateral lower extremities with similar imaging patterns on 99mTc-MDP bone scans. Glucose-6-phosphate dehydrogenase deficiency (G-6PD deficiency), Gaucher disease (GD), steroid-induced osteonecrosis, progressive diaphyseal dysplasia (PDD), Erdheim–Chester disease (ECD) and Langerhans cell sarcoma (LCS) were included and imaging characteristics were analyzed. The rare properties of these diseases and mimicking features on 99mTc-MDP bone scans rendered differential diagnosis difficult but necessary. We believe that the rarely known imaging features of the reported diseases will undoubtedly help nuclear medicine physicians make differential diagnoses in clinical practice.

Benign Bone Tumors: An Overview of What We Know Today

Nonmalignant bone tumors represent a wide variety of different entities but maintain many common features. They usually affect young patients, and most can be diagnosed through imaging exams. Often asymptomatic, they can be discovered incidentally. Due to their similarities, these tumors may be challenging to diagnose and differentiate between each other, thus the need for a complete and clear description of their main characteristics. The aim of this review is to give a picture of the benign bone tumors that clinicians can encounter more frequently in their everyday work.

A novel approach for fibrous dysplasia assessment using combined planar and quantitative SPECT/CT analysis of Tc-99m-diphosphonate bone scan in correlation with biological bone turnover markers of disease activity

Purpose

To investigate the emerging role of Tc-99m-labeled diphosphonate (Tc-99m-DPD) uptake quantification by SPECT/CT in fibrous dysplasia (FD) bone lesions and its correlation with biological bone turnover markers (BTMs) of disease activity.

Materials and methods

Seven patients (49 ± 16 years) with a confirmed diagnosis of FD were included in this retrospective study. Bone scans with Tc-99m-DPD and quantitative SPECT/CT (xSPECT/CT) were performed. SUV_max (maximum standard unit value) and SUV_mean (mean standard unit value) were measured in all FD bone lesions. The skeletal burden score (SBS) was assessed on planar scintigraphy and multiplied by mean SUV _max and SUV_mean to generate two new parameters, SBS_SUV_max and SBS_SUV_mean, respectively. Planar and xSPECT/CT quantitative measures were correlated with biological BTMs of disease activity, including fibroblast growth factor 23 (FGF-23), alkaline phosphatase (ALP), procollagen 1 intact N-terminal propeptide (P1NP) and C-terminal telopeptide (CTX), as well as scoliosis angle measured on radiographs. Statistical significance was evaluated with Spearman's correlations.

Results

A total of 76 FD bone lesions were analyzed, showing an average SUV_max and SUV_mean (g/mL) of 13 ± 7.3 and 8 ± 4.5, respectively. SBS, SBS_SUV_max and SBS_SUV_mean values were 30.8 ± 25.6, 358 ± 267 and 220.1 ± 164.5, respectively. Mean measured values of FGF-23 (pg/mL), ALP (U/L), P1NP (μg/L) and CTX (pg/mL) were 98.4 (22-175), 283.5 (46-735), 283.1 (31-1,161) and 494 (360-609), respectively. Mean scoliosis angle was 15.7 (7-22) degrees. We found a very strong positive correlation between planar-derived SBS and CTX (r = 0.96, p = 0.010), but no significant correlation between SUV_max or SUV_mean and biological BTMs. SBS_SUV_max showed a strong to very strong positive correlation with CTX (ρ = 0.99, p = 0.002), FGF-23 (ρ = 0.91, p = 0.010), ALP (ρ = 0.82, p = 0.020), and P1NP (ρ = 0.78, p = 0.039), respectively.

Conclusion

This study showed that biological BTMs are significantly correlated with diphosphonate uptake on bone scan, quantified by a new parameter combining information from both planar and quantitative SPECT/CT. Further analysis of bone scan quantitative SPECT/CT data in a larger patient population might help better characterize the skeletal disease burden in FD, and guide treatment and follow-up.

Mimics of Erdheim-Chester disease

Erdheim-Chester disease (ECD) is a rare histiocytic neoplasm with frequent multiorgan involvement. An accurate diagnosis of ECD requires the correlation of clinical features, histopathologic and radiologic findings. We describe a case series of patients with a referral diagnosis of ECD, whereby the diagnosis was changed to non-histiocytic diseases after comprehensive review at a tertiary care center. This accurate revision of the referral diagnosis of ECD enabled initiation of proper disease-directed therapy in a timely manner for these patients and avoided unnecessary exposure to systemic cytotoxic chemotherapy or targeted agents. Our study highlights the value of a multidisciplinary team of histiocytosis experts in confirming the diagnosis of ECD and also brings attention to other conditions to consider that can mimic ECD, including osteopoikilosis, tenosynovial giant cell tumour, IgG4-related disease, fibrous dysplasia and chronic recurrent multifocal osteomyelitis.

Enchondroma in the Diaphysis of Tibia - A Case Report and Review of its Characteristics and Differentials in the Diaphysis

Introduction

Enchondroma is a solitary, benign, intramedullary cartilaginous tumor commonly noticed in the phalanges of hands and feet with characteristic radiological features. Its occurrence in aberrant sites with atypical features lead to diagnostic dilemma. Enchondromas which are usually managed non-operatively can mimic other benign and malignant lesions, especially chondrosarcoma.

Case Report

We report the case of a 31-year-old farmer who presented with long standing inconspicuous pain in his left leg which turned out to be a diaphyseal enchondroma even though it demonstrated aggressive radiological features mimicking a chondrosarcoma. Incisional biopsy was done from the scalloped areas to obtain the correct histological diagnosis. He underwent thorough curettage of the lesion and remains asymptomatic 2 years after the procedure. We attempt to discuss the differentials which the orthopedic surgeon should keep in mind for diaphyseal lesions mimicking enchondroma.

Conclusion

Though classically found in metaphysis, Enchondromas are not uncommon in diaphysis of long bones. Enchondromas are generally benign, but can cause diagnostic dilemma when they present with aggressive features at rare locations and surgeons should be wary of the differentials. Despite a size of more than 6 cm and evidence of cortical erosion and intramedullary widening, the lesion could still be benign. Early biopsy will help to differentiate Enchondroma from a malignant transformation or malignant tumor.

Wedge Osteotomy with Tens Nailing in Monostotic Fibrous Dysplasia of Tibia - A Case Report

Introduction

Titanium elastic nailing (TENS) with wedge osteotomy for the management of monostotic fibrous dysplasia (FD) of tibia is done in a 6-year-old male patient.

Case Report

This is a case describing monostotic FD of right tibia in a 6-year-old male patient. The patient’s parents noticed a diffuse swelling in the right leg a few days after birth. It was managed conservatively till 3 years of age when the patient started complaining of pain in his right leg and difficulty in walking and running. The patient developed gradual and progressive anterior bowing in the right leg in the next 3 years. The patient was diagnosed with monostotic FD of the right tibia based on clinical and radiological findings. Wedge osteotomies were done in the tibia and fibula with TENS nailing as a definitive procedure for this patient.

Discussion

Management of monostotic FD of the right tibia with TENS nailing and wedge osteotomy can be a possible modality of definitive management with complete pain relief and deformity correction.

Conclusion

Correction of deformities secondary to FD requires meticulous pre-operative planning and execution. But with proper planning, even major deformities as in our case, procedures as simple as wedge osteotomy and TENS nailing can give excellent outcomes.

Acquired Facial, Maxillofacial, and Oral Asymmetries—A Review Highlighting Diagnosis and Management

Facial asymmetry refers to the absence of, or the deviation from the regular mirror image of facial structures, relative to a referenced midline axis. It can be attributed to a wide spectrum of deformities, including congenital, developmental, or acquired conditions, which can originate either prenatally or postnatally. Though highly prevalent, asymmetry commonly goes undiagnosed due to its subtle or relative nature. Among the spectrum of conditions, acquired cases are triggered postnatally, in previously normal individuals, thus subjecting them to sudden, eventful psychological and psychosocial disharmony. When detected early, timely management may help intervene progressive growth of these conditions. This, therefore, emphasizes the need for a thorough diagnostic workup including medical/dental history, clinical examinations, study models, photographic and radiographic records for a case-by-case basis to prevent severe functional and aesthetic complications. Recently, advanced diagnostic procedures, such as stereophotogrammetry, 3D stereolithographic models, skeletal scintigraphy (radionucleotide scans), 3D computed tomographic scans, cone-beam computed tomography, and magnetic resonance imaging, have provided innovative diagnostic instruments for numerous craniofacial defects. This descriptive review aims at focusing on the factors leading to frequently encountered conditions of acquired facial asymmetry and highlights their clinical evaluation, conservative and surgical interventions by a multi-disciplinary team of clinicians.

Surgical Treatment of Fibrous dysplasia in the Maxillary Bone of a 12 Year-Old Girl: A Case Report

Fibrous dysplasia is a rare bony disorder with recurrent character distinguished by abnormal fibro-osseous tissue. One or more bones may be involved in this lesion; however, the maxilla is the most commonly affected bone in the maxillofacial region. Here, we present an interesting case of a surgically treated 12-year-old adult female patient with a diagnosis of craniofacial fibrous dysplasia (CFD) in the maxillary bone with an invasive expansion to the orbital bone who was referred to the Department of Oral and Maxillofacial, Mashhad Dental School, Mashhad, Iran, in Apr 2021. The patient was treated under general anesthesia by the surgical recontouring and bone shaving of the tumor. Several factors should be considered in choosing the best treatment such as pathological features of the lesion, patient's age, and risk of recurrence. However, surgical treatment, in this case, was beneficial to help the patient resuming a normal life. There is no published report describing bone recontouring and shaving management in an invasive case of craniomaxillofacial FD before the age of skeletal maturity due to the psychological effect of the deformity.

Increased uptake of 68Ga-DOTA-FAPI-04 in bones and joints: metastases and beyond

PURPOSE

To describe the uptake of ⁶⁸Gallium-labelled fibroblast activation protein inhibitor (⁶⁸Ga-FAPI) in the bones and joints for better understanding of the role of ⁶⁸Ga-FAPI PET in benign and malignant bone lesions and joint diseases.

METHODS

All 129 ⁶⁸Ga-FAPI PET/MR or PET/CT scans from June 1, 2020, to February 20, 2021, performed at our PET center were retrospectively reviewed. Foci of elevated ⁶⁸Ga-FAPI uptake in the bones and joints were identified. All lesions were divided into malignant and benign diseases. Benign lesions included osteofibrous dysplasia, periodontitis, degenerative bone diseases, arthritis, and other inflammatory or trauma-related abnormalities. The number, locations, and SUVmax of all lesions were recorded and analyzed. The detectability of ⁶⁸Ga-FAPI PET and ¹⁸F-FDG PET in patients who had two scans was also compared.

RESULTS

Elevated uptake of ⁶⁸Ga-FAPI in/around the bones and joints was found in 82 cases (63.57%). A total of 295 lesions were identified, including 94 (31.9%) malignant lesions (all were metastases) and 201 (68.1%) benign lesions. The benign lesions consisted of 13 osteofibrous dysplasia, 48 degenerative bone disease, 33 periodontitis, 56 arthritis, and 51 other inflammatory or trauma-related abnormalities. The spine, shoulder joint, alveolar ridge, and pelvis were the most commonly involved locations. Bone metastases were mainly distributed in the spine, pelvis, and ribs. Among benign diseases, periodontitis and arthritis are site-specific. The mean SUVmax of bone metastases was significantly higher than that of benign diseases (7.14 ± 4.33 vs. 3.57 ± 1.60, p < 0.001), but overlap existed. The differences in SUVmax among subgroups of benign diseases were statistically significant (p < 0.001), with much higher uptake in periodontitis (4.45 ± 1.17). ⁶⁸Ga-FAPI PET identified much more lesions than ¹⁸F-FDG PET (104 vs. 48) with higher uptake value.

CONCLUSION

⁶⁸Ga-FAPI accumulated in both bone metastases and some benign diseases of the bones and joints. Although the uptake of ⁶⁸Ga-FAPI was often higher in bone metastases, this finding cannot be used to distinguish between benign and malignant lesions. ⁶⁸Ga-FAPI PET also has the potential to locate and evaluate the extent of both malignant tumor and benign diseases in bones and joints.

TRIAL REGISTRATION

NCT04554719, NCT04605939. Registered September 8, 2020 and October 25, 2020-retrospectively registered, http://clinicaltrails.gov/show/NCT04554719 ; http://clinicaltrails.gov/show/NCT04605939.

Imaging Spectrum of Calvarial Abnormalities

Calvarial abnormalities are usually discovered incidentally on radiologic studies or less commonly manifest with symptoms. This narrative review describes the imaging spectrum of the abnormal calvaria. The extent, multiplicity, and other imaging features of calvarial abnormalities can be combined with the clinical information to establish a final diagnosis or at least narrow the differential considerations. Prior trauma (congenital depression, leptomeningeal cysts, posttraumatic osteolysis), surgical intervention (flap osteonecrosis and burr holes), infection, and inflammatory processes (sarcoidosis) can result in focal bone loss, which may also be seen with idiopathic disorders without (bilateral parietal thinning and Gorham disease) or with (Parry-Romberg syndrome) atrophy of the overlying soft tissues. Anatomic variants (arachnoid granulations, venous lakes, parietal foramina) and certain congenital lesions (epidermoid and dermoid cysts, atretic encephalocele, sinus pericranii, and aplasia cutis congenita) manifest as solitary lytic lesions. Other congenital entities (lacunar skull and dysplasia) display a diffuse pattern of skull involvement. Several benign and malignant primary bone tumors involve the calvaria and manifest as lytic, sclerotic, mixed lytic and sclerotic, or thinning lesions, whereas multifocal disease is mainly due to hematologic or secondary malignancies. Metabolic disorders such as rickets, hyperparathyroidism, renal osteodystrophy, acromegaly, and Paget disease involve the calvaria in a more diffuse pattern. Online supplemental material is available for this article. ^©RSNA, 2021.

Imaging of Fibrous Dysplasia Protuberans, an Extremely Rare Exophytic Variant of Fibrous Dysplasia

This paper details the case report of a 26-year-old man who presented with a growing right-sided skull mass evaluated with ultrasound, non-contrast CT, contrast-enhanced MRI and ^99mTc-MDP whole body bone scan with SPECT/CT. These studies suggested a broad differential diagnosis favoring benign osseous lesions. Given a more recent increase in the rate of growth, headache and large size, the lesion was excised via craniotomy followed by cranioplasty. Pathology confirmed fibrous dysplasia (FD) as the diagnosis. Interestingly, this report is the imaging evaluation of the exophytic subtype of FD, the so-called FD protuberance, an extremely rare variant of FD, of which only two case reports are found in the literature.

Monostotic Fibrous Dysplasia of the Mandible in a 9-Year-Old Male Patient Treated with a Conservative Surgical Treatment: A Case Report and 15-Year Follow-Up

Fibrous dysplasia is a developmental disorder of the bone that originates from a genetic defect disturbing the osteogenesis leading to the replacement of normal bone with the excess proliferation of fibrous tissue. It can be associated with hyperpigmentation of the skin and endocrine disorders. Fibrous dysplasia can manifest in a monostotic form affecting one bone or in a polyostotic form involving several bones. Approximately 30% of monostotic forms are observed in the maxilla and the mandible. It frequently appears in the posterior region and is usually unilateral. It is found in teenagers and could become static after adulthood. Patients can present with swelling, facial asymmetry, pain, or numbness on the affected side. Treatment modalities vary between conservative surgical treatment, radical surgical approach, and medical treatment based on bisphosphonates. Here, we present a case of a monostotic form of fibrous dysplasia affecting the posterior left region of the mandible in a 9-year-old male complaining of gradually increased swelling on the left mandibular side of one-year duration. The diagnosis of fibrous dysplasia is established based on clinical, radiographical, and histopathological features. Conservative surgery is implemented with surgical shaving and reencountering of the bone excess to reduce the facial asymmetry. Recurrence is reported 10 years later and is also treated with a localized osteoplasty and remodeling of the bone contours. Five years later, the lesion remains stable. In conclusion, a conservative approach should be adopted as the first line of treatment for young patients suffering from monostotic fibrous dysplasia.

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.

Imaging characteristics of a rare case of monostotic fibrous dysplasia of the sacrum: A case report

BACKGROUND

Fibrous dysplasia (FD) is a common benign intramedullary fibro-osseous lesion. Involvement of the spine is rare, with the literature including only case reports, and cases of monostotic FD (MFD) in the sacrum are extremely rare. A correct preoperative diagnosis of spinal MFD is important for clinicians to select proper treatment.

CASE SUMMARY

We retrospectively assessed a case report of MFD in the sacrum. This patient was examined by computed tomography (CT) and magnetic resonance imaging (MRI), and the diagnosis was confirmed by pathology. A review of the literature was performed to analyze the imaging characteristics and differential diagnoses of spinal MFD. For our patient, the CT scan showed the lesion to be expansile, with ground glass opacity and a sclerotic rim. On MRI, the lesion showed iso-low signal intensity on T1WI and iso-high signal intensity on T2WI. A low signal rim was found on T1WI and T2WI. Our patient was treated by posterior focal excision, decompression, bone grafting, fusion and pedicle screw fixation. A satisfactory result was achieved, with pain disappearance. No complications had occurred at the 1-year follow up.

CONCLUSION

MFD is an expansile osteolytic change. Ground glass opacity and a sclerotic margin are obvious characteristics. The lesion often involves the vertebral body and posterior element. Knowledge of these imaging characteristics of spinal FD could be helpful for diagnosis and prevent unnecessary procedures.

Osteodystrophies of jaws

Bone is a dense, semi rigid, porous, calcified connective tissue forming the major portion of the skeleton of most vertebrates. It consists of a dense organic matrix and an inorganic mineral component. Bone remodelling is a complex process by which old bone is continuously replaced by new tissue, which requires interaction between different cell phenotypes and is regulated by a variety of biochemical and mechanical factors. In a homeostatic equilibrium, the process of resorption and formation are balanced so that old bone is continuously replaced by new tissue and it adapts to mechanical load and strain. Several local and systematic factors which cause disturbances in bone resorption and deposition leads to abnormal or defective development of bone commonly termed as osteodystrophy - A defective ossification of bone usually is associated with disturbed calcium and phosphorus metabolism. The better understanding of molecular cellular biology and pathogenic mechanism aids to define the abnormalities in osteoblastic and osteoclastic lineages and to develop new therapeutic approaches.

Fibrous dysplasia of the clivus - A case study and literature review

Fibrous dysplasia is a benign, congenital skeletal disorder which leads to the formation of fibro-osseous intramedullary bone lesions. Clival fibrous dysplasia is a rare variant which commonly presents asymptomatically with no findings on examination and is often picked up incidentally on radiological investigation. A 39-year-old female presented with a sudden onset headache of 3 days’ duration alongside diplopia and right lower limb weakness upon examination. Computerized tomography head scan revealed an expansile clivus with a ground-glass appearance, magnetic resonance imaging brain scan revealed a predominantly hypointense signal on T1- and T2-weighted images and subsequent whole-body bone imaging confirmed the diagnosis of monostotic clival fibrous dysplasia. This case highlights the importance of considering monostotic clival fibrous dysplasia as a differential diagnosis in patients presenting with sudden onset symptoms of headache alongside cranial and peripheral nerve involvement, when other more sinister causes have been excluded.

A Splint-to-CT Data Registration Strategy for Maxillary Navigation Surgery

Computer-assisted navigation plays an important role in modern craniomaxillofacial surgery. Although headpins and skull posts are widely used for the fixation of the reference frame, they require the use of invasive procedures. Headbands are easily displaced intraoperatively, thus reducing the accuracy of the surgical outcome. This study reported the utility of a novel splint integrated with a reference frame and registration markers for maxillary navigation surgery. A maxillary splint with a 10 cm resin handle was fabricated before surgery, to fix the reference frame to the splint. The splint was set after the incorporation of fiducial gutta-percha markers into both the splint and resin handle for marker-based pair-point registration. A computed tomography (CT) scan was acquired for preoperative CT-based planning. A marker-based pair-point registration procedure can be completed easily and noninvasively using this custom-made integrated splint, and maxillary navigation surgery can be performed with high accuracy. This method also provides maximum convenience for the surgeon, as the splint does not require reregistration, and can be removed temporarily when required. The splint-to-CT data registration strategy has potential applicability not only for maxillary surgery but also for otolaryngologic surgery, neurosurgery, and surgical repair after craniofacial trauma.

Kyphotic deformity of the lumbar spine due to a monostotic fibrous dysplasia of the second lumbar vertebra: a case report and its surgical management

Monostotic fibrous dysplasia (MFD) of the lumbar spine represents an exceedingly rare lesion. A 26-year-old patient presented with a progressive osteolytic lesion of the vertebral body L2 and the diagnosis of MFD. A minimally invasive left-sided eXtreme Lateral Interbody Fusion (XLIF) approach with resection of the vertebral body L2 with placement of a mesh cage was performed. No complications were observed perioperatively and the symptoms rapidly improved. Minimally invasive piecemeal resection with a combined dorsolateral approach showed a favorable clinical and radiological outcome and seems to be a safe and reliable technique for MFD.

Evaluation of natural growth rate and recommended age for shaving procedure by volumetric analysis of craniofacial fibrous dysplasia

BACKGROUND

We evaluated the preoperative natural growth pattern of craniofacial fibrous dysplasia and postoperative volume changes in patients undergoing shaving procedures.

METHODS

Thirty-three patients who underwent serial computed tomography (CT) preoperatively and/or postoperatively were identified. The natural tumor growth rate was assessed using preoperative CT scans. The postoperative tumor regrowth rates and relevant variables were analyzed.

RESULTS

The preoperative tumor growth rates were significantly lower in patients aged ≥ 16 years than in those aged < 16 years (P < .001). The postoperative tumor regrowth rates were significantly greater when a shaving operation was performed at age < 16 years than at age ≥ 16 years (P = .04). In patients with clinical recurrence, the postoperative remnant tumor volume was inversely correlated with the tumor regrowth rate.

CONCLUSIONS

The tumor growth rate of craniofacial fibrous dysplasia significantly decreased after age 16. This should be considered when conducting functional and aesthetic assessments in planning for the shaving of craniofacial fibrous dysplasia.

Pathological Fracture of the Tibia in a Monostotic Anterior Cortical Fibrous Dysplasia: Hybrid Fixation with UnicorticalOsteoperiosteal Non-Vascularized Fibula Graft - A Case Report

Introduction

Fibrous Dysplasia is a relatively rare Musculoskeletal disorders in which there is a defect in remodelling of immature bone to mature lamellar bone. Fibrous Dysplasia was first described by Von Recklinghausen in 1891, but it was Lichtenstein who labelled it polyostotic Fibrous Dysplasia in 1938. Union of Pathological Fractures in a bone affected by Fibrous Dysplasia poses a difficult set of Challenges for treating Physicians.

Case Report

We Report a 24 year-old female patient with a Pathological Fracture of the Tibia in a Monostotic Anterior Cortical Fibrous Dysplasia Hybrid Fixation with a UnicorticalOsteoperisoteal Non Vascularized Fibula Graft with a follow up until the union of fracture site on computed tomography scan and complete integration of unicorticalosteoperiosteal fibular graft .

Conclusion

We provide additional and independent evidence that removal of the diseased cortex which were parts of the proximal and distal fragment and reconstruction of the defect in the cortex with a press- fitunicortical Non vascularized osteoperiosteal fibular strut graft with a hybrid fixation is a good treatment modality for monostotic fibrous dysplasia. Hybrid fixation includes retrograde intramedullary transarticular rodding extending across the subtalar and ankle joint into the tibia and augmentation of the primary fixation with a mono-planar rail Fixation in compression mode.

Advances in Sensing Technologies for Monitoring of Bone Health

: Changing lifestyle and food habits are responsible for health problems, especially those related to bone in an aging population. Poor bone health has now become a serious matter of concern for many of us. In order to avoid serious consequences, the early prediction of symptoms and diagnosis of bone diseases have become the need of the hour. From this inspiration, the evolution of different bone health monitoring techniques and measurement methods practiced by researchers and healthcare companies has been discussed. This paper focuses on various types of bone diseases along with the modeling and remodeling phenomena of bones. The evolution of various diagnosis tests for bone health monitoring has been also discussed. Various types of bone turnover markers, their assessment techniques, and recent developments for the monitoring of biochemical markers to diagnose the bone conditions are highlighted. Then, the paper focuses on the potential assessment of the recent sensing techniques (physical sensors and biosensors) that are currently available for bone health monitoring. Considering the importance of electrochemical biosensors in terms of high sensitivity and reliability, specific attention has been given to the recent development of electrochemical biosensors and significance in real-time monitoring of bone health.

Continued growth of locally aggressive fibrous dysplasia of 22 years duration after reaching adulthood: a case report

Fibrous dysplasia generally stops growing when patients reach adulthood. Locally aggressive fibrous dysplasia is an extremely rare subtype of fibrous dysplasia that is characterized by progressive enlargement after bone maturation, cortical bone destruction and soft tissue invasion but without malignant transformation. At 50 years of age, a tumor was found in the rib of a patient. The tumor gradually enlarged over time and imaging findings suggested a malignant tumor. The case was further complicated by restrictive lung disorder. Biopsies from multiple sites showed no malignant findings, and marginal resection with partial curettage was performed. The final diagnosis was locally aggressive fibrous dysplasia, and the restrictive lung disorder improved postoperatively. The natural history of the disease is also unknown. This is the first report in the literature to describe a case in which a lesion exhibited long-term growth over a period of 22 years after reaching adulthood.

Fibro-osseous Lesions of Paranasal Sinus and Craniofacial Region: A Retrospective Study of 282 Cases

OBJECTIVES

To compare the clinical characteristics of osteoma, ossifying fibroma (OF) and fibrous dysplasia (FD) in the paranasal sinus and craniofacial regions.

METHODS

Totally 282 patients (112 males, 170 females) with osteoma (161), OF (44), and FD (77) involving the paranasal sinus, skull base and orbit treated surgically from January 2012 to August 2018 were analyzed retrospectively.

RESULTS

For osteoma, OF and FD, the onset ages were 40.3 (6-75), 24.5 (5-62), and 15 (1-63) years, and the most common locations were ethmoid sinus (49.7%), maxilla (36.4%) and maxilla (49.4%), respectively. There were significant differences of the preoperative serum alkaline phosphatase (ALP) levels between patients with osteoma (65 [25,184] U/L), OF (85.5 [41,474] U/L), and FD (104 [39,362] U/L) (Z = 44.9, P < .05). The ALP levels of OF and FD patients were comparable between monostotic and polyostotic lesions (P > .05). The recurrent rates of osteoma, OF, and FD were 0%, 13.6%, and 15.6%, respectively. The recurrent OF cases had significantly higher ALP level than the primary ones (283.5 [108,474] U/L vs. 76 [41,348] U/L, U = 14, P < .05).

CONCLUSION

There are differences in the onset age, location, and recurrence rate among osteoma, OF and FD involving the paranasal sinus and craniofacial region. Osteoma most commonly occurs in the ethmoid sinus, while OF and FD involve the maxilla most and are more likely to involve the orbit and the skull base, respectively. Endoscopic surgery is currently the main method for treatment, but individualized treatment regimen should be developed for patients.

LEVEL OF EVIDENCE

IV Laryngoscope, 131:E1-E7, 2021.

Changes in gene expression in human skeletal stem cells transduced with constitutively active Gsα correlates with hallmark histopathological changes seen in fibrous dysplastic bone

Fibrous dysplasia (FD) of bone is a complex disease of the skeleton caused by dominant activating mutations of the GNAS locus encoding for the α subunit of the G protein-coupled receptor complex (Gsα). The mutation involves a substitution of arginine at position 201 by histidine or cysteine (Gsα^{R201H or R201C}), which leads to overproduction of cAMP. Several signaling pathways are implicated downstream of excess cAMP in the manifestation of disease. However, the pathogenesis of FD remains largely unknown. The overall FD phenotype can be attributed to alterations of skeletal stem/progenitor cells which normally develop into osteogenic or adipogenic cells (in cis), and are also known to provide support to angiogenesis, hematopoiesis, and osteoclastogenesis (in trans). In order to dissect the molecular pathways rooted in skeletal stem/progenitor cells by FD mutations, we engineered human skeletal stem/progenitor cells with the Gsα^R201C mutation and performed transcriptomic analysis. Our data suggest that this FD mutation profoundly alters the properties of skeletal stem/progenitor cells by pushing them towards formation of disorganized bone with a concomitant alteration of adipogenic differentiation. In addition, the mutation creates an altered in trans environment that induces neovascularization, cytokine/chemokine changes and osteoclastogenesis. In silico comparison of our data with the signature of FD craniofacial samples highlighted common traits, such as the upregulation of ADAM (A Disintegrin and Metalloprotease) proteins and other matrix-related factors, and of PDE7B (Phosphodiesterase 7B), which can be considered as a buffering process, activated to compensate for excess cAMP. We also observed high levels of CEBPs (CCAAT-Enhancer Binding Proteins) in both data sets, factors related to browning of white fat. This is the first analysis of the reaction of human skeletal stem/progenitor cells to the introduction of the FD mutation and we believe it provides a useful background for further studies on the molecular basis of the disease and for the identification of novel potential therapeutic targets.

A Clinical Perspective on Advanced Developments in Bone Biopsy Assessment in Rare Bone Disorders

Introduction: Bone biopsies have been obtained for many centuries and are one of the oldest known medical procedures in history. Despite the introduction of new noninvasive radiographic imaging techniques and genetic analyses, bone biopsies are still valuable in the diagnosis of bone diseases. Advanced techniques for the assessment of bone quality in bone biopsies, which have emerged during the last decades, allows in-depth tissue analyses beyond structural changes visible in bone histology. In this review, we give an overview of the application and advantages of the advanced techniques for the analysis of bone biopsies in the clinical setting of various rare metabolic bone diseases. Method: A systematic literature search on rare metabolic bone diseases and analyzing techniques of bone biopsies was performed in PubMed up to 2019 week 34. Results: Advanced techniques for the analysis of bone biopsies were described for rare metabolic bone disorders including Paget's disease of bone, osteogenesis imperfecta, fibrous dysplasia, Fibrodysplasia ossificans progressiva, PLS3 X-linked osteoporosis, Loeys-Diets syndrome, osteopetrosis, Erdheim-Chester disease, and Cherubism. A variety of advanced available analytical techniques were identified that may help to provide additional detail on cellular, structural, and compositional characteristics in rare bone diseases complementing classical histopathology. Discussion: To date, these techniques have only been used in research and not in daily clinical practice. Clinical application of bone quality assessment techniques depends upon several aspects such as availability of the technique in hospitals, the existence of reference data, and a cooperative network of researchers and clinicians. The evaluation of rare metabolic bone disorders requires a repertoire of different methods, owing to their distinct bone tissue characteristics. The broader use of bone material obtained from biopsies could provide much more information about pathophysiology or treatment options and establish bone biopsies as a valuable tool in rare metabolic bone diseases.

Response to Zoledronic Acid Infusion in Children With Fibrous Dysplasia

Objective: This retrospective study evaluated the outcome and safety of long-term treatment with zoledronic acid, in both polyostotic and mono-ostotic fibrous dysplasia (FD) of children. Methods: The case records of children and adolescents with symptomatic FD who received zoledronic acid (0.1 mg/kg IV infusion over 1 h) and have completed at least 2 years follow-up were analyzed. The relevant details were recorded in a predesigned chart. Clinical assessment [pain assessment by visual analog scale (VAS) and incidence of new fracture], radiological changes (cortical thickening, ossification, and decrease in the diameter of the osteolytic lesions) and biochemical parameters [alkaline phosphatase (ALP)] were used to evaluate the improvement. Results: The mean age of presentation was 9.1 years, with four males and six females. All patients had symptomatic FD in the lower limb with complaints of pain, tenderness, swelling, or deformity. Four children had associated pathological fracture. The radiological evaluation with bone scan revealed polyostotic involvement in eight patients and mono-ostotic involvement in two patients. Three patients had associated systemic features like café-au-lait spots or precocious puberty. The fracture united within 3 months and the radiological improvement was evident in the form of filling of the osteolytic defect. The pain score in six patients showed significant improvement (VAS < 3). The ALP level decreased to 544.12 ± 47.35 IU/L from an initial value of 895.75 ± 79.64 IU/L (p = 0.04) at 12 months. One patient had symptomatic hypocalcaemia after zoledronic acid infusion. Conclusion: The clinical and radiological response of zoledronic acid treatment in FD of children is promising. Further randomized control trials with a larger sample size are required to establish this drug as a first-line medical treatment in FD.

Magnetic resonance imaging characteristics in patients with histopathologically proven fibrous dysplasia-a systematic review

OBJECTIVE

To examine the demographics, lesion location, and characteristic magnetic resonance imaging (MRI) findings in patients with histopathologically proven fibrous dysplasia (FD).

MATERIALS AND METHODS

A systematic literature search of the MRI findings in patients with histologically proven FD was performed. Altogether, 76 articles with 136 patients were evaluated.

RESULTS

The mean age of the patients was 35.0 + - 18.5 years (range 1 month-75 years). Fifty-eight of the cases were females, 51 males, and in 27 gender was not defined. The most common locations were craniofacial (n = 55 (40%)), long bones (n = 31 (23%)), and spine (n = 24 (18%)). The monostotic form of FD was the most common. Signal intensities (SI) on T1-weighted images were predominantly hypointense (n = 46 (37%)). The SI was highly variable on T2-weighted images with hyperintensity being most common (n = 22 (18%)). Contrast enhancement was found in 75 (55%) FD patients. Secondary aneurysmal bone cysts (ABCs) and malignant transformation in patients without prior radiotherapy was found in some patients.

CONCLUSION

Current knowledge of the MRI findings in patients with FD is based mainly on case reports. SI in patients with FD is variable and contrast enhancement is common. FD may explain etiology of spinal bone tumor in some patients. FD with malignant transformation should be considered also in patients without prior radiotherapy. Further studies are needed to clarify if FD displays specific characteristics allowing it to be distinguished from other bone tumors.

Monostotic fibrous dysplasia at C7 treated with vertebroplasty: a case report and review of the literature

Background

Monostotic fibrous dysplasia (MFD) involving the spine is rare, and the treatment options are controversial. Surgery is needed when patients suffer from persistent pain, spinal cord compression/injury, and vertebral collapse/instability. Treatment methods include biopsy/observation, corpectomy with instrumented fusion, posterior fusion, vertebroplasty (VP), curettage and bone graft, and complete removal of the vertebra with a combined anterior and posterior fusion procedure.

Case presentation

The patient was a 56-year-old woman with a 2-year history of neck pain. No obvious abnormalities were detected on neurological or physical examination, and laboratory findings were all within normal limits. An imaging examination suggested a C7 vertebral bone tumor. The patient refused to continue conservative observation treatment and requested surgery. Open VP of the C7 vertebral body was carried out, and her postoperative neck pain was completely relieved. The postoperative pathological results supported the diagnosis of fibrous dysplasia, and the patient was ultimately diagnosed with MFD. At the 12-month follow-up visit, the patient reported no clinical symptoms, and no signs of tumor recurrence were detected.

Conclusion

VP can relieve pain while stabilizing the spine. Thus, the surgical treatment of MFD vertebral lesions by VP is a valuable option.

Subxiphoid uniportal video-assisted thoracoscopic surgery: A cosmetically superior approach to submammary rib tumor resection

This report describes a cosmetically superior approach to submammary rib tumor resection. Surgical resection is the most effective method for the treatment of rib tumors. Common surgical methods include thoracotomy and thoracoscopic surgery. Subxiphoid uniportal video‐assisted thoracoscopic surgery (VATS) has recently been described and is being increasingly used in a variety of thoracic procedures, including thymectomy, lobectomy, and resection of giant pleural fibroids. However, there has been no report in the literature which has described the use of uniportal subxiphoid VATS for rib tumor resection. We herein report the successful removal of fibrous dysplasia of the anterolateral segment of the sixth rib by subxiphoid uniportal VATS.

Unusual Presentation of Fibrous Dysplasia in an Elderly Patient

Fibrous Dysplasia is a benign fibro-osseous lesion occurring throughout the skeletal system with a predilection for craniofacial bones, long bones, and ribs. Fibrous dysplasia develops during bone formation and growth with a variable natural evolution. It is considered a genetic nonheritable disease resulting from missense mutations that occur postzygotically in the GNAS1 gene. This mutation leads to a focal congenital failure of proper bone formation and arrest at the woven bone stage. In turn, this leads to a decreased mechanical strength, causing bone pain, pathological fractures, and skeletal deformities. Besides clinical examination, fibrous dysplasia is diagnosed based on the results of radiographic imaging and the microscopic histopathological findings. On CT scan, fibrous dysplasia shows the characteristic "Ground-glass" appearance with well-defined borders. On MRI, fibrous dysplasia has a low signal intensity on T1-weighted MRI and variable signal intensity on T2-weighted MRI. We hereby report a case of an unusual presentation of fibrous dysplasia in a 67-year-old female presenting to the emergency department with generalized malaise and lower limb pain. Fibrous dysplasia may present in the elderly population and can be difficult to differentiate from other malignant and benign lesions affecting the skeletal system.

[The activating GNAS mutation : A survey of fibrous dysplasia, its associated syndromes, and other skeletal and extraskeletal lesions]

Fibrous dysplasia of bone is a connatal but not hereditary disease with monostotic or polyostotic manifestations and may be associated either with the extraskeletal disease McCune-Albright syndrome or with myxoma of the skeletal muscle, termed Mazabraud syndrome.The confirmation of recurrent chromosomal aberrations may lead to the conclusion that fibrous dysplasia is a neoplasia rather than a dysplastic skeletal disease.The primary cause of all forms of the described diseases is the activating GNAS mutation, which is detectable in almost all lesions. Research into the impact of this mutation has increased the understanding of these up to now solely descriptively defined diseases and also allowed easier discrimination of various fibro-osseous skeletal lesions. Current insights suggest that this mutation may also play a pivotal role in other extraskeletal neoplasias.

Permian metabolic bone disease revealed by microCT: Paget's disease-like pathology in vertebrae of an early amniote

Bone remodeling is an essential physiological process in growth and healing. In modern systems deviations from normal bone physiology in the form of pathologies aid in the understanding of normal bone metabolism. Here we use external morphology and X-ray microtomography to diagnose and describe a metabolic bone disease in an amniote from the early Permian. The specimen consists of two fused tail vertebrae of a small varanopid from early Permian (289 million years old) cave deposits near Richards Spur, Oklahoma, USA. Inspection of the outer morphology reveals that the fusion encompasses the vertebral centra, zygopophyses and haemal arches, with the fusion zones distinctly swollen on the left side of the specimen. With visualization of its internal structure by microCT, this specimen is diagnosed as a complex metabolic bone disease. The radiological imaging suggests a pathologically high bone turnover rate, as shown by abnormal bone formation in some areas and increased bone resorption in others. This supports that the varanopid suffered from a metabolic bone disease similar to Paget’s disease of bone as seen in humans today, which is linked to both genetic and viral factors. This finding extends the occurrence of Paget-like disease to the early Permian, and–provided a viral component was present–would also be by far the oldest evidence of viral infection in the fossil record.

Pain in fibrous dysplasia: relationship with anatomical and clinical features

Background and purpose - Fibrous dysplasia (FD) is a rare bone disorder associated with pain, deformities, and pathological fractures. The pathophysiological mechanism of FD-related pain remains ill-understood. We evaluated the degree of pain and the potential contributory factors in 2 patient cohorts from Austria and the Netherlands. Patients and methods - 197 patients (16-85 years) with FD (Graz n = 105, Leiden n = 92) completed a survey concerning the presence and severity of pain at their FD site. Sex, age, type of FD, and localization of FD lesions were examined for a relationship with the presence and severity of pain. Results - Of 197 patients from the combined cohort (61% female, mean age 49 (SD 16) years, 76% monostotic) who completed the questionnaires, 91 (46%) reported pain at sites of FD lesions. Severity of pain was higher in patients with lesions of the lower extremities and ribs compared with upper extremity or craniofacial lesions. Severe subtypes of FD (polyostotic/McCune-Albright syndrome) were more often associated with pain, often severe. Interpretation - Our data suggest that almost 50% of patients with FD report pain at FD sites, thus representing a major clinical manifestation of the disorder, importantly also in patients with monostotic lesions. Lesions in lower extremities and ribs were more painful.

Fibrous dysplasia of occipital and temporal bone. A case report

Fibrous dysplasia is a rare non-malignant condition where fibrous tissue replaces the normal bone architecture. Involvement of temporal and occipital bones is exceptionally rare and is associated with unique complications. A 10-year-old boy presented with right retroauricular enlargement and pain. Imaging studies and biopsy revealed fibrous dysplasia of the temporal and occipital bones. There was no hearing loss or sequelae arising from posterior fossa compression. The patient was discharged with follow-up instructions. Only 10 cases of occipital bone fibrous dysplasia have been reported in the medical literature. Occipital bone fibrous dysplasia can be complicated with Chiari malformation and syringomyelia while temporal bone involvement is associated with hearing loss. These potential developments require close follow-up that includes detailed neurologic examination, imaging and audiology.