Imaging Findings of Fibrous Dysplasia with Histopathologic and Intraoperative Correlation

Forget Me Not: Incidental Findings on Breast MRI

With the growing utilization and expanding role of breast MRI, breast imaging radiologists may encounter an increasing number of incidental findings beyond the breast and axilla. Breast MRI encompasses a large area of anatomic coverage extending from the lower neck to the upper abdomen. While most incidental findings on breast MRI are benign, identifying metastatic disease can have a substantial impact on staging, prognosis, and treatment. Breast imaging radiologists should be familiar with common sites, MRI features, and breast cancer subtypes associated with metastatic disease to assist in differentiating malignant from benign findings. Furthermore, detection of malignancies of nonbreast origin as well as nonmalignant, but clinically relevant, incidental findings can significantly impact clinical management and patient outcomes. Breast imaging radiologists should consistently follow a comprehensive search pattern and employ techniques to improve the detection of these important incidental findings.

Bone and soft tissue tumors at the borderlands of malignancy

This review examines findings of musculoskeletal neoplasms whose equivocal imaging and/or histopathologic features make it difficult to determine if they will show aggressive behavior. We include both intermediate tumors as defined by the World Health Organization (WHO), and a single low-grade malignancy, low-grade central osteosarcoma, which mimics a benign lesion on imaging and histology. Intermediate tumors are a broad category and are subdivided into tumors that have risk of local recurrence only, and ones that have a risk of distant limb and pulmonary metastases. Difficult intermediate musculoskeletal lesions include atypical cartilaginous tumor/grade 1 chondrosarcoma, atypical lipomatous tumor/grade 1 liposarcoma, and solitary fibrous tumor. We review diagnostic criteria, differential diagnosis, and recommendations for surveillance.

Ectopic Fibrous Dysplasia Presenting As a Well-Circumscribed Orbital Mass

The authors present the case of a middle-aged woman with subacute progressive swelling of the OD associated with pain and severely limited duction in all gazes. MRI demonstrated a ~3 cm circumscribed mass in the extraconal space, which displaced and distorted the globe and impinged upon ocular adnexa. She underwent lateral orbitotomy with bone osteotomy to remove the mass, and subsequent histopathologic examination showed woven bone set within a fibrotic background, microscopic features of fibrous dysplasia. Fibrous dysplasia is characterized by abnormal scar-like bony proliferation, typically within a preexisting structure of the skeletal system. To the authors' knowledge, this represents the first example of fibrous dysplasia presenting as an orbital mass unconnected to the craniofacial skeleton.

Neglected huge chest wall mass. A case report of fibrous dysplasia

INTRODUCTION

fibrous dysplasia is a slow-growing bone tumor and is caused by the failure of bone maturation. It is usually asymptomatic thus it is generally found incidentally in radiologic evaluations. Computed tomography is the best radiologic modality for its evaluation. The characteristic findings are ground-glass lesions surrounded by a rim or shell of reactive bone.

PRESENTATION OF CASE

This study presents a 52-year-old male patient with a huge chest wall tumor arising from the posterolateral aspect of the right fourth to seventh ribs measuring 38 cm. He underwent a thoracotomy and the tumor was resected. For safe margin, the third and eighth ribs were also resected. The defect was reconstructed with a prolene mesh patch and a pectoralis major flap. The final pathology report stated a tumor composed of spindle cells without pleomorphism or mitotic figures with intervening branching and anastomosing bone trabeculae. The margins were tumor-free and on the follow-up, the patient's condition was decent.

DISCUSSION

Primary tumors of the rib account for 5 % to 7 % of all primary bone neoplasms. Fibrous dysplasia makes up 0.8 % of primary bone tumors. Fibrous dysplasia usually causes no symptoms although it can get massive enough to get symptomatic. Its diagnosis is made through clinical, radiological, and histopathological investigations. CT scan findings are the cornerstone for radiologic evaluations. An individualized approach based on the patient's age and symptoms should be considered.

CONCLUSION

Considering that the malignant degeneration of the tumor is uncommon, early diagnosis and surgical resection of the tumor can be curative.

Comparison of MRI Findings among Osteofibrous Dysplasia, Fibrous Dysplasia, and NonOssifying Fibroma of the Long Bone

Background The characteristics of magnetic resonance imaging (MRI) findings among osteofibrous dysplasia (OFD), fibrous dysplasia (FD), and nonossifying fibroma (NOF) have yet to be determined.

Aims This study determines the differences of MRI features among OFD, FD, and NOF of the long bone.

Patients and Methods This study included 39 patients including 10 OFD, 13 with FD, and 16 with NOF of the long bone. All patients underwent preoperative MRI and histological examination. We retrospectively reviewed the MRIs and compared the imaging findings among the three pathologies.

Results The maximum diameter was significantly different among OFD (47.0 ± 18.6 mm), FD (59.0 ± 35.0 mm), and NOF (33.3 ± 15.0 mm) (p < 0.05). Multiplicity (60%, p < 0.01), eccentric distribution (100%, p < 0.05), septation (70%, p < 0.01), homogeneous intensity on T2-weighted images (70%, p < 0.01), homogeneous contrast enhancement (63%, p < 0.05), and intense contrast enhancement (88%, p < 0.01) were significantly more frequent in OFD. Centric distribution (69%, p < 0.01), cyst formation (54%, p < 0.01), and fluid-fluid level formation (31%, p < 0.01) were significantly more frequent in FD. Eccentric distribution (100%, p < 0.01), heterogeneous on T2-weighted images (100%, p < 0.01), predominant hypointensity on T2-weighted images (44%, p < 0.01), and the presence of intralesional hypointensity on T2-weighted images (88%, p < 0.01) were significantly more frequent in NOF.

Conclusion MRI features could differentiate OFD, FD, and NOF of the long bone.

Benign Bone Lesions Found in Childhood

Benign bone tumors are a wide variety of usually asymptomatic neoplasms, which in most cases are diagnosed due to secondary causes. As such, their real incidence is unknown. In the majority of cases, plain radiographs are enough for diagnosis; more advanced imaging, such as CT scan or MRI is sometimes performed for equivocal lesions. Treatment approach depends on whether the lesion is symptomatic and the risk of further progression, or development of secondary malignancies. When non expectant management is decided, treatment options include minimally invasive methods and surgery.

McCune-Albright syndrome with acromegaly: A case report with characteristic radiographic features of fibrous dysplasia

McCune-Albright syndrome (MAS) is a rare multisystem disorder characterized by a clinical triad of polyostotic fibrous dysplasia (FD), skin pigmentation, and hyperfunctioning endocrinopathies. A 42-year-old man visited our medical hospital for the treatment of intermittent headaches and was diagnosed with MAS with acromegaly. This patient showed various clinical features of MAS, including pituitary adenoma, polyostotic FD, and hypogonadotropic hypogonadism. The FD lesions showed characteristic radiographic features, such as widespread, sclerotic bony lesions in the cranial bones, mixed radiolucent-radiopaque multilocular lesions in the mandible, and radiolucent lesions in the axial and appendicular skeleton. Over the years, the patient had been hospitalized multiple times due to accidental bony fractures associated with the fragile bony state of FD. This report presents a retrospective description of a case of MAS, with a review of the relevant literature.

Incidental osseous lesions on chest CT: an algorithmic approach for radiologists

Numerous osseous findings are commonly discovered incidentally at chest CTs in daily practice. A broad spectrum of these findings ranges from benign and do not touch lesions to ominous conditions requiring further imaging evaluation and/or intervention. Interpretation of these incidental musculoskeletal findings may constitute a diagnostic challenge to radiologists. This review provides a systematic, algorithmic approach to common osseous lesions on chest CT based on imaging findings with recommendations for proper next step management.

The West China Hospital radiographic classification for fibrous dysplasia in femur and adjacent bones: A retrospective analysis of 205 patients

Objective

This study aims to investigate the reliability and clinical outcome of a newly developed classification system for patients with fibrous dysplasia (FD) of the femur and adjacent bones, optimizing its evaluation and management.

Methods

A total of 205 patients (121 female and 84 male) with FD in the femur and adjacent bones were included in this retrospective study. All affected femurs were measured and treated based on this classification at our institution between 2009 and 2019. Based on previous studies and extensive clinical follow‐up, we cautiously proposed the West China Hospital radiographic classification for FD in femur and adjacent bones following corresponding treatment options. There are five types with five radiographic features, including proximal femur bone loss, coxa vara, femoral shaft deformity, genu valgum, and hip arthritis. The intraobserver and interobserver reproducibility of this classification was assessed by four observers using the Cohen kappa statistic. The clinical outcome was evaluated using the criteria of Guille.

Results

At a median follow‐up of 60 months (range 6–120), 205 patients (median 34.8 years old, range 18–73 years old) were categorized into the following five types: Type I 31.7%, Type II 30.2%, Type III 20.5%, Type IV 10.2%, and Type V 7.3%. The mean interobserver and intraobserver kappa scores were 0.85 (range 0.77–0.89) and 0.85 (range 0.79–0.92), respectively. For clinical outcomes, there was no significant difference in the postoperative Guille score for Type I patients (mean 9.01 ± 1.22). There was a significant increase in the postoperative Guille score in Type II, III, IV, and V, compared to the preoperative values (P < 0.01). For complications, two Type III patients reported pain, and one Type III patient had mild‐to‐moderate Trendelenburg gait. One Type IV patient had a mild Trendelenburg gait. And two Type V patients still had mild limping.

Conclusion

This classification is reproducible and serves as a tool for evaluating and treating FD in the femur and adjacent bones. Therefore, we recommend this classification for the diagnosis and treatment of FD‐related deformities in the femur and adjacent bones.

Anatomy and Diseases of the Greater Wings of the Sphenoid Bone

The greater wings of the sphenoid bone (GWS) comprise the components of the sphenoid bone that make up most of the posterior orbital wall and form the anterior and medial parts of the floor of the middle cranial fossa. Many important skull base foramina, which transmit vital neurovascular structures, are present in these paired wings on either side of the central body of the sphenoid bone. A wide variety of diseases can affect the GWS, ranging from benign osseus lesions to malignant primary and secondary bone abnormalities. The complex three-dimensional curved (winged) shape of the GWS and the wide array of pathologic entities that affect this bone can make it challenging for the radiologist to report the imaging findings accurately, especially in relation to the important skull base foramina. The authors describe a systematic approach to understanding the three-dimensional anatomy of the GWS and review important diseases, with the aid of imaging examples. Useful imaging "pearls" that can help in making specific diagnoses are provided throughout the article. ^©RSNA, 2022.

Fibrous dysplasia animal models: A systematic review

BACKGROUND

Fibrous dysplasia (FD) is a rare genetic bone disorder resulting in an overproduction of cAMP leading to a structurally unsound tissue, caused by a genetic mutation in the guanine nucleotide-binding protein gene (GNAS). In order to better understand this disease, several animal models have been developed with different strategies and features.

OBJECTIVE

Conduct a systematic review to analyze and compare animal models with the causative mutation and features of FD.

METHODS

A PRISMA search was conducted in Scopus, PubMed, and Web of Science. Studies reporting an in vivo model of FD that expressed the causative mutation were included for analysis. Models without the causative mutation, but developed an FD phenotype and models of FD cell implantation were included for subanalysis.

RESULTS

Seven unique models were identified. The models were assessed and compared for their face validity, construct validity, mosaicism, and induction methods. This was based on the features of clinical FD that were reported within the categories of: macroscopic features, imaging, histology and histomorphometry, histochemical and cellular markers, and blood/urine markers.

LIMITATIONS

None of the models reported all features of FD and some features were only reported in one model. This made comparing models a challenge, but indicates areas where further research is necessary.

CONCLUSION

The benefits and disadvantages of every model were assessed from a practical and scientific standpoint. While all published reports lacked complete data, the models have nonetheless informed our understanding of FD and provided meaningful information to guide researchers in bench and clinical research.

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 Review of Posteromedial Lesions of the Chest Wall: What Should a Chest Radiologist Know?

A heterogeneous group of tumors can affect the posteromedial chest wall. They form diverse groups of benign and malignant (primary or secondary) pathologies that can arise from different chest wall structures, i.e., fat, muscular, vascular, osseous, or neurogenic tissues. Chest radiography is very nonspecific for the characterization of chest wall lesions. The modality of choice for the initial assessment of the chest wall lesions is computed tomography (CT). More advanced cross-sectional modalities such as magnetic resonance imaging (MRI) and positron emission tomography (PET) with fluorodeoxyglucose are usually used for further characterization, staging, treatment response, and assessment of recurrence. A systematic approach based on age, clinical history, and radiologic findings is required for correct diagnosis. It is essential for radiologists to be familiar with the spectrum of lesions that might affect the posteromedial chest wall and their characteristic imaging features. Although the imaging findings of these tumors can be nonspecific, cross-sectional imaging helps to limit the differential diagnosis and determine the further diagnostic investigation (e.g., image-guided biopsy). Specific imaging findings, e.g., location, mineralization, enhancement pattern, and local invasion, occasionally allow a particular diagnosis. This article reviews the posteromedial chest wall anatomy and different pathologies. We provide a combination of location and imaging features of each pathology. We will also explore the role of imaging and its strengths and limitations for diagnosing posteromedial chest wall lesions.

Society of Skeletal Radiology- white paper. Guidelines for the diagnostic management of incidental solitary bone lesions on CT and MRI in adults: bone reporting and data system (Bone-RADS)

The purpose of this article is to present algorithms for the diagnostic management of solitary bone lesions incidentally encountered on computed tomography (CT) and magnetic resonance (MRI) in adults. Based on review of the current literature and expert opinion, the Practice Guidelines and Technical Standards Committee of the Society of Skeletal Radiology (SSR) proposes a bone reporting and data system (Bone-RADS) for incidentally encountered solitary bone lesions on CT and MRI with four possible diagnostic management recommendations (Bone-RADS1, leave alone; Bone-RADS2, perform different imaging modality; Bone-RADS3, perform follow-up imaging; Bone-RADS4, biopsy and/or oncologic referral). Two algorithms for CT based on lesion density (lucent or sclerotic/mixed) and two for MRI allow the user to arrive at a specific Bone-RADS management recommendation. Representative cases are provided to illustrate the usability of the algorithms.

[The experience of interdisciplinary interaction in elimination of midface deformation (clinical observation)]

Fibrous dysplasia is a hamartoma appearing as a benign pathologic process in which normal bone tissue formation is replaced by overgrowth of fibrous connective tissue. The problem of diagnosis and treatment of patients with fibrous dysplasia remains unsolved in the absence of a uniform understanding of its etiology and pathogenesis. Treatment and rehabilitation of patients with midface fibrous dysplasia is a complicated medico-social problem, which requires interaction of specialists of different fields to resolve it. The disease presents a practical interest for doctors of more than 20 specialties, as it can lead to disability. The present article describes a clinical case of interdisciplinary interaction of specialists in the fields of maxillofacial surgery, ophthalmology, otorhinolaryngology, plastic surgery and radiology involved in complex treatment of a patient with midface fibrous dysplasia accompanied by eyeball dislocation, decreased vision, as well as progressive impairment of nasal breathing function. The performed treatment resulted in favorable functional and aesthetic outcomes including elimination of exophthalmos, vertical strabismus, lacrimation disorders, nasal breathing disorders, increase of visual acuity and improvement of external appearance.

Magnetic resonance imaging of the orbit, Part 2: Characterization of orbital pathologies

In this article we focus on a systematic approach to assess common orbital lesions on magnetic resonance imaging (MRI). The identification of the probable compartment or structure of origin helps narrow the differential diagnosis of a lesion. Analyzing the morphology, appearance, and signal intensity on various sequences, the pattern, and degree of contrast enhancement are key to characterize lesions on MRI. Imaging features suggesting cellularity and vascularity can also be determined to help plan for biopsy or surgery of these lesions. MRI can also distinguish active from chronic disease in certain pathologies and aids in selecting appropriate medical management. MRI may thus serve as a diagnostic tool and help in guiding therapeutic strategies and posttreatment follow-up.

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.

Jaffe Lichtenstein Type of Polyostotic Skeletal Fibrous Dysplasia With the Involvement of Cranial Bones

ABSTRACT

Fibrous dysplasia (FD), a benign fibro-osseous bone tumor commonly involving the craniofacial region, presents a wide spectrum of radiographic patterns. When FD lesions are suspected, various imaging modalities and histopathologic analyses may be required to reach a firm diagnosis. Here, the authors report the case of a 10-year-old male patient presenting with polyostotic type of FD with follow-up data for the next 9 years. The patient showed involvement of cranial bones and bilateral femurs, with skin pigmentation and no endocrine disease, consistent with the diagnosis of Jaffe Lichtenstein disease. The craniofacial radiographic features obtained with computed tomography and cone-beam computerized tomography are documented in this article.

Clinical pathological characteristics of pelvic bone tumors

Introduction: Bone tumors are rare neoplasms whose therapy depends on the location. Pelvic bones represent a special anatomical entity diagnosis and therapy of pelvic tumors in addition to the pathohistological type largely depends on the anatomical specifics of that region. Aim: The aim of this study was to show the frequency, as well as clinical and pathological characteristics of primary and secondary tumors of the pelvic bones. Material and methods: The research as a descriptive study in the period from January 1, to December 31, 2019 at the Institute of Pathology of the Medical Faculty of the University of Belgrade and includes 33 patients. Demographic, clinical and radiological data were obtained from the Bone Tumor Registry. Statistical processing and analysis were done in the Statistical Package for Social Science SPSS Windows version 22 (IBM Chicago, Ilinois, USA). Results: Out of 33 patients, 55% had secondary pelvic tumors, primarily cancer metastases (37%). In 21% of cases, primary malignant bone tumor as diagnosed, and in 12%, primary benign bone tumor. Hematopoietic neoplasms were verified in 12%. Conclusion: Pelvic bone tumors are not common, but these neoplasms, in orthopedic oncology, represents their malignant biological behavior are of great importance. The most common primary malignant tumor in adults is chondrosarcoma, and in children Ewing sarcoma. Highest frequency for pelvic bone metastases has lung cancer. Plasmacytoma in adults, Langerhans cellular histiocytosis in children are hematological neoplasms seen at this site.

Osteosarcomatous Transformation in Mazabraud Syndrome: A Case Report

Mazabraud 증후군은 다골성 섬유성 이형성과 근육 내 점액종이 동반되는 매우 드문 양성 질환이다. 섬유성 이형성에서 악성 변환이 일어나는 경우는 약 1%로 알려져 있고, Mazabraud 증후군의 섬유성 이형성에서 발생한 골육종으로 악성 변환에 대한 보고는 아직까지 전 세계에 8예에 불과하다. 저자들은 Mazabraud 증후군 환자에서 섬유성 이형성이 있었던 경골에 골육종이 발생한 증례를 경험하였기에 영상 소견을 중심으로 대한민국에서 처음으로 보고한다.

Tumor-like Lesions of Bone and Soft Tissues and Imaging Tips for Differential Diagnosis

In the musculoskeletal system, tumor-like lesions may present similar imaging findings as bone and soft tissue tumors and can be defined as tumors on radiologic examinations. Misinterpretation of the imaging findings can lead to inappropriate clinical management of the patient.There is still some debate regarding the pathophysiology and origin of tumor-like lesions that include congenital, developmental, inflammatory, infectious, metabolic, reactive, posttraumatic, post-therapeutic changes, and some miscellaneous entities causing structural changes. Although tumor-like lesions are historically defined as non-neoplastic lesions, some of them are classified as real neoplasms.We discuss a spectrum of entities mimicking tumors of bone and soft tissues that include various non-neoplastic diseases and anatomical variants based on imaging findings.

Soft Tissue Special Issue: Gnathic Fibro-Osseous Lesions and Osteosarcoma

Gnathic fibro-osseous lesions are a diverse group of disease processes which share overlapping microscopic features characterized by fibroblastic stroma with variable cellularity and a range of bone forming pathological processes leading to woven, sclerotic and cementum-like structures. Some of the lesions are unique to craniofacial location and a combination of clinical, radiological and pathological correlation is often necessary for diagnostic accuracy. Gnathic osteosarcomas are rare tumors with differences in age distribution and behavior as compared to osteosarcoma of long bones. This review will discuss the clinicopathological and radiological features of gnathic fibro-osseous lesions and osteosarcoma with updates on current genetics and molecular pathogenesis.

Fibrous dysplasia as a possible false-positive finding in 68Ga-labeled prostate-specific membrane antigen positron emission tomography/computed tomography study in the follow-up of prostate cancer

Positron emission tomography/computed tomography (PET/CT) using ⁶⁸Ga-labeled prostate-specific membrane antigen (⁶⁸Ga-PSMA) has become an important tool in restaging patients with prostate cancer (PCa). Despite its high sensitivity and specificity, this method may produce false-positive findings, as indicated by previous studies. This case report aims to warn nuclear medicine physicians, oncologists, and urologists about the possibility of false-positive findings using this imaging modality, especially when the detected site is unusual for bone metastasis. A 68-year-old man with PCa underwent restaging tests after presenting with increased prostate-specific antigen. ⁶⁸Ga-PSMA PET/CT imaging revealed abnormal uptake in the left humeral head, which anatomically corresponded to the intramedullary and cortical sclerotic area. A biopsy was performed, and the pathology showed a lesion consisting of hard bone tissue with a small focal spot of fibrous dysplasia. Diagnostic issues related to ⁶⁸Ga-PSMA PET/CT imaging should be disseminated to help physicians make appropriate treatment choices for each patient.

Heterogeneity of 68Ga-PSMA PET/CT Uptake in Fibrous Dysplasia

Fibrous dysplasia is an uncommon benign bone pathology with only rare potential for malignant transformation. We describe the heterogeneous uptake of fibrous dysplasia of a whole rib on Ga-labeled prostate-specific membrane antigen (PSMA) PET/CT. Ga-PSMA binds to PSMA-expressing prostate cancer cells, but it can also bind to the neovasculature of various solid tumors, as well as to some benign lesions. Ga-PSMA expression in fibrous dysplasia should not automatically be equated with malignant transformation or confused with prostate cancer metastases.

Osteoma-like melorheostosis: a rare type of skeletal dysplasia depicted on FDG PET/CT

Melorheostosis, also known as Leri's disease, is a rare benign form of mesodermal mixed sclerosing bone dysplasia. We report the unusual case of a 14-year-old boy with melorheostosis in the lower extremity that went undiagnosed due to concurrent Ewing sarcoma in the opposite limb, confounding the findings for metastatic disease. The diagnosis was made on FDG PET/CT when the patient presented for post Ewing sarcoma treatment follow-up. The different types of melorheostosis as well as the challenge of diagnosing this rare entity are discussed in this report.

Best practice management guidelines for fibrous dysplasia/McCune-Albright syndrome: a consensus statement from the FD/MAS international consortium

Fibrous Dysplasia / McCune Albright syndrome (FD/MAS) represents a wide spectrum of diseases due to somatic gain-of-function mutations of the GNAS gene. The mutation leads to overactivity in the target tissues and to a wide phenotype of clinical features that vary in severity and age of onset. The rarity of the disease and its variable presentation to multiple specialities often leads to misdiagnosis and inappropriate variability in investigations and treatments. To address this, our international consortium of clinicians, researchers, and patients’ advocates has developed pragmatic clinical guidelines for best clinical practice for the definition, diagnosis, staging, treatment and monitoring for FD/MAS to empower patients and support clinical teams in both general and specialised healthcare settings. With the lack of strong evidence to inform care, the guidelines were developed based on review of published literature, long-standing extensive experience of authors, input from other healthcare professionals involved in the care of FD/MAS patients and feedback from patients and patient groups across the globe. This has led to the formulation of a set of statements to inform healthcare professionals, patients, their families, carers and patient groups of the best practice of care. It is anticipated the implementation of these recommendations will lead to improvement in the care of patients with FD/MAS internationally.

Polyostotic Fibrous Dysplasia Mimicking Osseous Metastases

Fibrous dysplasia (FD) is a benign bone disorder, in which normal bone structure is replaced by fibrous connective tissue. Polyostotic FD is also related to McCune-Albright syndrome with possible endocrine disorder and Cafe-au-lait macules. Although FD commonly presents as craniofacial bone abnormality, atypical presentation can be misleading and pose a difficulty in clinical diagnosis. Here we report a case of polyostotic FD, who presented as an accidental finding of multiple spinal osseous lesions, leading to clinic workup for metastatic cancer.

Surgical Treatment of Cervical Spine Fibrous Dysplasia: Case Report and Literature Review

Background

Fibrous dysplasia (FD) is an uncommon benign intramedullary fibro-osseous lesion. Cervical spine compromise is rare with only cases reported. Currently, the natural history of cervical FD is poorly understood, and its treatment remains controversial.

Methods

A review of the literature was performed to analyze and discuss the management of cervical FD through a case report and literature review.

Results

Cervical FD is a rare benign pathology. Clinical presentation is usually casual or only clinical pain. Computed tomography (CT)-guided percutaneous biopsy is a safe and effective technique for evaluation of spinal lesions; however, the accuracy of the preoperative biopsy findings has been disappointing. Although all treatments are valid, no one has been demonstrated to be better. Our proposed treatment, a corpectomy and fixation with a titanium mesh cage filled with allograft bone and an anterior cervical plate, showed good results.

Conclusions

The rarity of cervical FD and the lack of detailed reports with long-term follow-up periods complicate the research on the optimal treatment approach in these cases, but apparently all are valid for pain control. In our case, a corpectomy and fixation with a titanium mesh cage filled with allograft bone and an anterior cervical plate was carried out and showed good results. We submit this surgery option to be considered in these rare type of injuries.

Atypical localization of intraosseous angioleiomyoma in the rib of a pediatric patient: a case report

BACKGROUND

This is the first reported case of a primary intraosseous angioleiomyoma and the second case of a primary leiomyoma of the rib, irrespective of age. Angioleiomyomas mostly occur in patients of advanced age, in any part of the body, particularly the lower extremities and present as painful, slow-growing nodules in the dermis, subcutaneous fat or deep fascia. Other localizations, especially bone, are considered extremely rare, as well as their occurrence in paediatric patients.

CASE PRESENTATION

A 10-year-old girl was admitted to the orthopaedic surgery department for further assessment of a pain localized in the posterior part of the right hemithorax. After magnetic resonance imaging (MRI) and surgical biopsy, intraosseus angioleiomyoma of the fourth rib was diagnosed by histopathology examination. Atypical costal localization of this type of a benign tumour presents diagnostic difficulty, especially in children. The differential diagnoses included cartilaginous tumours, Ewing sarcoma, fibrous dysplasia, Langerhans cell histiocytosis, intraosseous haemangioma and metastatic tumours. We report a detailed diagnostic procedure including MRI, selective angiography and histopathologic examination.

CONCLUSION

Diagnosis of intraosseous angioleiomyoma is difficult due to the extreme rarity of this tumour and absence of pathognomonic radiological signs. Although very rarely identified in bones and young age group, radiographers and reporting doctors should be aware of this possible angioleiomyoma presentation and supported by the provided detailed diagnostic information.

Gαs signaling controls intramembranous ossification during cranial bone development by regulating both Hedgehog and Wnt/β-catenin signaling

How osteoblast cells are induced is a central question for understanding skeletal formation. Abnormal osteoblast differentiation leads to a broad range of devastating craniofacial diseases. Here we have investigated intramembranous ossification during cranial bone development in mouse models of skeletal genetic diseases that exhibit craniofacial bone defects. The GNAS gene encodes Gα_s that transduces GPCR signaling. GNAS activation or loss-of-function mutations in humans cause fibrous dysplasia (FD) or progressive osseous heteroplasia (POH) that shows craniofacial hyperostosis or craniosynostosis, respectively. We find here that, while Hh ligand-dependent Hh signaling is essential for endochondral ossification, it is dispensable for intramembranous ossification, where Gα_s regulates Hh signaling in a ligand-independent manner. We further show that Gα_s controls intramembranous ossification by regulating both Hh and Wnt/β-catenin signaling. In addition, Gα_s activation in the developing cranial bone leads to reduced ossification but increased cartilage presence due to reduced cartilage dissolution, not cell fate switch. Small molecule inhibitors of Hh and Wnt signaling can effectively ameliorate cranial bone phenotypes in mice caused by loss or gain of Gnas function mutations, respectively. Our work shows that studies of genetic diseases provide invaluable insights in both pathological bone defects and normal bone development, understanding both leads to better diagnosis and therapeutic treatment of bone diseases.

Magnetic resonance imaging features of craniofacial fibrous dysplasia

Purpose

To assess the value of magnetic resonance imaging (MRI) in detecting craniofacial fibrous dysplasia (CFD) and diagnosing and differentiating it from intraosseous meningioma. Additionally, the MRI appearance of the typical computed tomography (CT) imaging feature, the ground glass phenomenon, was evaluated.

Material and methods

MRI datasets of 32 patients with CFD were analysed retrospectively. Detectability in MRI was assessed by analysis of 10 randomly selected patients with CFD and 10 normal controls by two blinded readers. Changes of affected bone, internal lesion structure, T1 and T2 signal intensity, and contrast enhancement of the lesion in general and ground glass areas in particular were assessed. Ten patients with intraosseous meningioma (one in each) served as differential diagnosis for CFD.

Results

All 10 CFD lesions were reliably detected in MRI. In 32 patients 36 CFD lesions were evaluated. In 66.7% CFD were iso- to hypointense in T1 and hyperintense in T2; this proportion was similar for ground glass areas (65.7%). Ground glass areas were more homogeneously structured than the whole CFD lesion in both T1 (100% vs. 56%, respectively) and T2 (91% vs. 61%, respectively). Contrast enhancement was found in 97% of complete CFD lesions and 93% of ground glass areas. The accuracy for CFD vs. intraosseous meningioma was 100% for 'no soft-tissue component' and 98% for 'bone broadening' in MRI.

Conclusions

Distinct morphological changes of CFD are reliably detected in MRI and allow differentiation from intraosseous meningioma. Areas with ground glass phenomenon in CT show a predominantly homogenous internal structure in MRI with contrast enhancement.

Fibrous dysplasia: an unusual case of a very aggressive form with costo-vertebral joint destruction and invasion of the contralateral D7 vertebral body

Fibrous dysplasia (FD) is a benign fibro-osseous disease of the bone that may be solitary or multicentric. It is important to distinguish this type of lesion from low-grade osteosarcomas (LGOS) and from secondary sarcomas, because malignant transformation has rarely been reported. It is classically described as having a ground-glass appearance, endosteal scalloping, and thinning of the cortex. Cortical disruption is considered evidence of malignancy, but it can also be present in benign FD with aggressive behavior. We present an unusual case of aggressive FD of the 7th left rib, already diagnosed more than 22 years ago, where cortical and costo-vertebral joint disruption and 7th thoracic vertebral body involvement were not evidence of malignant behavior. From a histological perspective, FD and LGOS are similar; even if histology is of fundamental importance, the diagnosis has to be made based on the clinical and radiological aspects as well, although at imaging, differentiation between FD and LGOS can be difficult. In the present case, even though the histological examination suggested a benign lesion, the radiological examination instead consistently suggests malignancy. It is for this reason that there should be a high index of suspicion during follow-up and a new biopsy should be scheduled in case any changes occur during follow-up.

Advanced Unilateral Fibrous Dysplasia of the Scapula: A Rare Clinical Entity and Surgical Challenge

Introduction:

Fibrous dysplasia (FD) is an uncommon benign tumor of bone. Although FD can affect flat bones, it is rare for the scapula to be involved. In addition, little is known about the management of FD when it involves the scapula. We present possibly the first comprehensive case report of the management of advanced unilateral FD of the scapular region.

Case Report:

A 47-year-old male presented to us with pain and swelling over the left shoulder. The swelling was 11 cm × 15 cm × 8 cm and was hard and tender with rough texture. Radiograph showed large homogenous lesion with irregular but well-defined margins and a ground glass appearance. Magnetic resonance imaging scans showed well-defined borders with the expansion of the bone, with intact overlying cortices and endosteal scalloping. Biopsy confirmed the lesion to be FD. An innovative application of an existing surgical technique to minimize the impact of the residual deformity and dead space left after curettage of the scapula was done. The patient had good clinical and functional outcome at 6-month follow-up.

Conclusion:

Surgical exercise in FD is purely on symptomatic basis. In our case, the swelling was causing most discomfort, and we curettaged and compressed the bony swelling which resulted in excellent outcome in this patient.

Computed Tomography and Magnetic Resonance Imaging Manifestations of Spinal Monostotic Fibrous Dysplasia

Aim:

The purpose of the study was to analyze and summarize the computed tomography (CT) and magnetic resonance imaging (MRI) findings of spinal monostotic fibrous dysplasia (MFD) as well as evaluate the clinical value of CT and MRI in MFD diagnosis.

Materials and Methods:

CT (n = 4) and MRI (n = 5) images of six patients with pathologically confirmed spinal MFD were examined. The assessed image features included location, shape, rib involvement, vertebral collapse, margin, attenuation, and sclerotic rim on CT, as well as signal intensity, dark signal rim, and enhancement pattern on MRI.

Results:

In total, four of six patients underwent CT scanning. The most common findings on CT scanning were expansile lesions (n = 4), sclerotic rims (n = 4), and ground-glass opacity (GGO) (n = 4). In total, five of six patients underwent MRI. The lesions were low-signal intensity (n = 2), low-to-isointense signal intensity (n = 1), and low-signal intensity with several isointense portions (n = 2) on T1-weighted imaging (T1WI). The lesions were low-signal intensity (n = 1), isointense to high intensity (n = 1), and isointense signal intensity with several high portions (n = 3) on T2WI. A dark signal rim was found in most cases on T1WI and T2WI (n = 4). The lesions (n = 2) showed obvious enhancement.

Conclusions:

The CT and MRI manifestations of spinal MFD have the following characteristics: expansile lesion, GGO, sclerotic rim, and no obvious soft-tissue mass. The combined use of CT and MRI examinations is necessary for patients with suspected spinal MFD.

Fibrous dysplasia of bone: Surgical management options and outcomes of 22 cases

The surgical treatment for fibrous dysplasia (FD) of bone is problematic due to its variable clinical courses. And multifarious surgical treatment options have been reported while no consistent view can be reached. Therefore, we reviewed a series of 22 patients (11 males and 11 females; mean age 28.4 years, range 15-48 years) with FD between December 2011 and July 2015. Fourteen patients had monostotic fibrous dysplasia (MFD) and eight patients had polyostotic fibrous dysplasia (PFD) with nine lesions. All patients were followed up from 15 to 58 months with an average of 26.0 months. Functional and radiographic outcomes were recorded. In the MFD group, four patients were treated with curettage and bone grafting without internal fixation and nine were treated with curettage and bone grafting with internal fixations. Osteotomy and intramedullary (IM) nail was applied in one patient with serious deformity. In the PFD group, three deformity lesions were treated with osteotomy and proximal femoral nail anti-rotation (PFNA). IM were also applied in six large lesions to treat fracture or prevent deformity. One lesion in tibia were treated with only curettage and bone graft. No complication was observed in MFD group and satisfactory union and functional outcomes acquired during follow-up period. In the PFD group, the spiral blade cutting out from femoral head in PFNA was observed in one patient and treated with revision surgery. No other complication occurred, and satisfactory radiological and functional outcome were observed. The severity of both MFD and PFD are related to size, site and of the lesion. The goal of the surgery is to eliminate pain, correct deformity and treat pathological fracture. Curettage, bone grafting with internal fixation is recommended for treating large lesions with deformity or high pathological fracture risk. PFNA or IM nail is prior in osteotomy with better clinical outcome.

Nontraumatic intradiploic arachnoid cyst of the sphenoid bone

The intradiploic arachnoid cysts are rare radiological entities which are generally post-traumatic in nature and occur mostly in occipital region. We present a rare case of non-traumatic, asymptomatic intradiploic cyst of the greater wing of sphenoid in an elderly patient. The CT and MR imaging confirmed an intraosseous multiloculated cystic lesion which showed communication with the cerebrospinal fluid in anterior temporal fossa, through the small bony defects.

Masses of developmental and genetic origin affecting the paediatric craniofacial skeleton

Although rare, masses and mass-like lesions of developmental and genetic origin may affect the paediatric craniofacial skeleton. They represent a major challenge in clinical practice because they can lead to functional impairment, facial deformation and disfigurement. The most common lesions include fibrous dysplasia, dermoid cysts, vascular malformations and plexiform neurofibromas. Less common lesions include torus mandibularis and torus palatinus, cherubism, nevoid basal cell carcinoma syndrome, meningoencephalocele and nasal sinus tract. This article provides a comprehensive approach for the evaluation of children with masses or mass-like lesions of developmental and genetic origin affecting the craniofacial skeleton. Typical findings are illustrated and the respective roles of computed tomography (CT), cone beam CT (CBCT), magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) sequences and ultrasonography (US) are discussed for the pre-therapeutic assessment, complex treatment planning and post-treatment surveillance. Key imaging findings and characteristic clinical manifestations are reviewed. Pitfalls of image interpretation are addressed and how to avoid them. TEACHING POINTS: • Masses of developmental and genetic origin may severely impair the craniofacial skeleton. • Although rare, these lesions have characteristic imaging features. • CT, MRI and ultrasonography play a key role in their work-up. • Recognition of pivotal imaging pearls and diagnostic pitfalls avoids interpretation errors.

Craniofacial Manifestations of Systemic Disorders: CT and MR Imaging Findings and Imaging Approach

Many systemic diseases or conditions can affect the maxillofacial bones; however, they are often overlooked or incidentally found at routine brain or head and neck imaging performed for other reasons. Early identification of some conditions may significantly affect patient care and alter outcomes. Early recognition of nonneoplastic hematologic disorders, such as thalassemia and sickle cell disease, may help initiate earlier treatment and prevent serious complications. The management of neoplastic diseases such as lymphoma, leukemia, or Langerhans cell histiocytosis may be different if diagnosed early, and metastases to the maxillofacial bones may be the first manifestation of an otherwise occult neoplasm. Endocrinologic and metabolic disorders also may manifest with maxillofacial conditions. Earlier recognition of osteoporosis may alter treatment and prevent complications such as insufficiency fractures, and identification of acromegaly may lead to surgical treatment if there is an underlying growth hormone-producing adenoma. Bone dysplasias sometimes are associated with skull base foraminal narrowing and subsequent involvement of the cranial nerves. Inflammatory processes such as rheumatoid arthritis and sarcoidosis may affect the maxillofacial bones, skull base, and temporomandibular joints. Radiologists should be familiar with the maxillofacial computed tomographic and magnetic resonance imaging findings of common systemic disorders because these may be the first manifestations of an otherwise unrevealed systemic process with potential for serious complications. Online supplemental material is available for this article. ^©RSNA, 2018.

Post-traumatic fibrous dysplasia of the parietal bone: A rare entity

Fibrous dysplasia (FD) is a rare fibro-osseous lesion in which normal bone is replaced by abnormal fibrous tissue. Although a congenital disorder, a single case report of traumatic etiology had been described in the literature. We report a case of monostotic FD of the parietal calvarium in a 21-year-old female patient who presented to us with a single swelling in the parietal region been noticed after head injury sustained at the age of 7 years. After imaging investigations, the lesion was excised via craniotomy followed by cranioplasty in the same sitting. The histopathological evidence was suggestive of FD. To the best of our knowledge, this is the second case of a posttraumatic cranial FD and the first case describing the growing mass in the parietal bone secondary to head injury.