Fibrous dysplasia involving the base of the skull

Fibrous dysplasia of paranasal sinuses with anterior skull-base extension presenting with pneumocephalus; a case report

Background

Fibrous dysplasia is a benign fibro-osseous lesion where normal bone is replaced with immature dysplastic woven bone and fibrous tissue. Fibrous dysplasia has the potential to involve multiple bones of the craniofacial area in a rare condition. Management of this involvement type should be assessed carefully.

Case report

Here, we report a 52-year-old man with progressive and bilateral frontal headache. The radio/pathologic diagnosis revealed fibrous dysplasia of paranasal sinuses with anterior skull-base extension and pneumocephalus. The patient underwent a craniotomy, and 2 weeks after the procedure, the symptoms were alleviated without any complications.

Conclusion

in case of fibrous dysplasia, patients with new onset and/or mild symptoms may have extensive lesions in multiple craniofacial bones.

The 'Eye Mask Sign' in Fibrous Dysplasia on 99mTc-MDP Skeletal Scintigraphy and SPECT/CT

Fibrous dysplasia (FD) is a fibro-osseous disorder that manifests with distinct or overlapping clinical patterns. FD may be monostotic or polyostotic and commonly associated with syndromes such as McCune-Albright syndrome and Mazabraud syndrome. We report a case of polyostotic FD with bilateral involvement of craniofacial bones in a distinct pattern and propose this characteristic appearance as the 'eye mask sign' on 99mTc-Methylene Diphosphonate (MDP) skeletal scintigraphy and SPECT/CT. Other unusual skeletal scintigraphic features noted in this case are also described (Figs. 1, 2, and 3).

Sphenoid sinus anatomical variants and pathologies: pictorial essay

The sphenoid sinus (SS) is one of the four paired paranasal sinuses (PNSs) within the sphenoid bone body. Isolated pathologies of sphenoid sinus are uncommon. The patient may have various presentations like headache, nasal discharge, post nasal drip, or non-specific symptoms. Although rare, potential complications of sphenoidal sinusitis can range from mucocele to skull base or cavernous sinus involvement, or cranial neuropathy. Primary tumors are rare and adjoining tumors secondarily invading the sphenoid sinus is seen. Multidetector computed tomography (CT) scan and magnetic resonance imaging (MRI) are the primary imaging modalities used to diagnose various forms of sphenoid sinus lesions and complications. We have compiled anatomic variants and various pathologies affecting sphenoid sinus lesions in this article.

Anterior and Central Skull Base Fibrous Dysplasia: A 12 Years' Experience

Fibrous dysplasia, specially of anterior and central skull base region, is a rare disorder. This article discusses about our experience in this pathology. A tertiary care institute based retrospective type study was conducted over a period of 12 years. Demographics, radiology, intraoperative details, pathology and follow up were taken into consideration and the data was analysed. Sixteen patients with complaints of proptosis, diplopia, nasal obstruction and/or facial deformity, underwent endoscopic sinus surgery. Subtotal resection was done in 5 patients. Ethmoid bone involvement was seen in 12 patients. Post operatively, diplopia persisted in one patient and one patient had epistaxis. All patients were followed up for 2-10 years with no other complications reported. Anterior and central skull base involvement is rare in fibrous dysplasia. However, it can be removed effectively by endoscopic approach. Overall safety of patient has more concern rather than complete removal of disease.

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.

A practical overview of CT and MRI features of developmental, inflammatory, and neoplastic lesions of the sphenoid body and clivus

The sphenoid bone is an unpaired bone that contributes to the formation of the skull base. Despite the enormous progress in transnasal endoscopic visualisation, imaging techniques remain the cornerstones to characterise any pathological condition arising in this area. In the present review, we offer a bird’s-eye view of the developmental, inflammatory, and neoplastic alterations affecting the sphenoid body and clivus, with the aim to propose a practical diagnostic aid for radiologists based on clinico-epidemiological, computed tomography, and magnetic resonance imaging features.

Bony Cyst in a Ground Glass Matrix: A Rare Case Report of Craniofacial Fibrous Dysplasia with Secondary Aneurysmal Bone Cyst

Fibrous dysplasia has various ways of presentation including syndromic associations and secondary changes within the lesion. We present a case of a 21-year-old female with craniofacial fibrous dysplasia, presenting with proptosis and intermittent blurring of vision due to focal fibrous dysplasia involving the frontal bone with secondary aneurysmal bone formation that was provisionally diagnosed on imaging and confirmed on histopathology. This case demonstrates the typical imaging findings of fibrous dysplasia with seldom encountered secondary aneurysmal bone cyst formation and also discusses about the pathology and management of the craniofacial fibrous dysplasia.

Clinical application of "black bone" imaging in paediatric craniofacial disorders

For decades, CT has been the primary imaging modality for the diagnosis and surveillance of paediatric craniofacial disorders. However, the deleterious effects of ionising radiation in the paediatric population are well established and remain an ongoing concern. This is especially so in the head and neck region, which has relatively poor soft tissue shielding with many radiosensitive organs. The development of "black bone" imaging utilising low flip angles and short echo time (TE) has shown considerable promise in alleviating the use of ionising radiation in many cases of craniofacial disorders. In this review article, we share our experience of utilising "black bone" sequence in children with craniofacial pathologies, ranging from traumatic injuries to craniosynostosis and focal osseous/fibro-osseous lesions such as fibrous dysplasia and Langerhans cell histiocytosis (LCH). A detailed discussion on the technical aspects of "black bone" sequence, including its potential pitfalls and limitations, will also be included.

Differential Diagnosis of Calvarial Tumors: A Series of 8 Cases

Introduction To present and discuss the clinical presentations, investigations, and treatment options for skull bone tumors.

Materials and Methods This study was conducted from January 2019 to December 2019 at the Department of Neurosurgery. During this period, eight patients presented with skull bone tumor in the outpatient department. All patients were thoroughly investigated. Surgery was conducted on six patients and two patients had disseminated carcinoma; hence, surgery was not done. Patients were regularly followed-up after the surgery.

Results In our study, out of eight cases, five were females and three were males. We had two cases of fibrous dysplasia, two cases of osteomas, and one case each of brown tumor, metastases from lung carcinoma, metastases from follicular carcinoma of thyroid, and Ewing sarcoma/primitive neuroectodermal tumor (PNET). Excision of tumor was performed where indicated and adjuvant chemo- and radiotherapy was suggested wherever required.

Conclusion Bony tumors of the skull are uncommon diseases for the neurosurgeons. These tumors require a careful diagnosis with suitable radiological examinations and proper clinical correlation for proper management.

Central Skull Base Anatomy and Pathology: A Review

The central skull base is an anatomically complex region of the head and neck which hosts a variety of neoplastic, vascular, infectious, inflammatory, and developmental pathologies. Evaluation of its intricate anatomy requires dedicated and complementary imaging modalities of MRI and CT. This article will provide a brief review of the anatomy of the central skull base, followed by an overview of common pathologies encountered in this region and their characteristic radiological characteristics.

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.

Fibrous Dysplasia, Paget's Disease of Bone, and Other Uncommon Sclerotic Bone Lesions of the Craniofacial Bones

Imaging studies of the brain, head and neck, sinuses, and dental computed tomography are among the most frequently performed procedures in radiologic departments. Systematic evaluation in the bone window may reveal common and uncommon sclerotic osseous abnormalities of the craniofacial skeleton.Most of these findings are incidental and unrelated to the initial clinical indications. Sporadically symptoms may arise due to lesional mass effect with compression on adjacent structures and neuroforaminal encroachment, resulting in proptosis, vision, or hearing loss. Other symptoms include craniofacial deformity, mandibular occlusion deformity, and local pain.This article reviews the most common disorders characterized by an increased bone density involving the craniofacial bones including fibrous dysplasia, Paget's disease of bone, meningioma with associated hyperostosis, and osteoma. Finally, typical examples of rarer sclerosing bone dysplasias are discussed as well.Emphasis is placed on imaging features and the differential diagnosis.

Imaging Findings in Non-Neoplastic Sinonasal Disease: Review of Imaging Features With Endoscopic Correlates

Non-neoplastic sinonasal disease is common and imaging often plays an important role in establishing the proper diagnosis, guiding clinical management, and evaluating for complications. Both computed tomography and magnetic resonance imaging are commonly employed in the imaging evaluation and it is important to understand the imaging characteristics of the unique types of pathology affecting the sinonasal cavities. This article reviews a variety of infectious, inflammatory, and other non-neoplastic sinonasal pathologies, highlighting imaging features that aid in their differentiation.

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.

Secondary Aneurysmal Bone Cyst in a Craniofacial Fibrous Dysplasia: Case Report

Aneurysmal bone cyst (ABC) is a rare non-neoplastic bone lesion that involves mostly the long bones and vertebrae and may occur very rarely in the craniofacial bones. ABCs may occur as secondary bony pathologies in association with various benign and malignant bone tumors and with fibrous dysplasia (FD). FD is a common non-neoplastic bony pathology mostly affecting craniofacial bones. Secondary ABC occurring in craniofacial FD is extremely rare, with only approximately 20 cases reported in the literature to date. Here, we report on a case of secondary ABC in a 25-year-old woman who has had a craniofacial deformity for over 10 years and who presented to us with a rapidly growing painful pulsatile mass in the right frontal region that began over 2 months prior to admission. On thorough examination of computed tomography and magnetic resonance imaging brain scans taken at two-month interval, an aggressive, rapidly enlarging ABC, arising from the right frontal FD, was diagnosed. The patient underwent preoperative embolization followed by gross total resection of the ABC and cranioplasty. The 6-month follow up showed no recurrence of the ABC, nor was any progression of the FD noticed.

Radiological review of skull lesions

Abstract

Calvarial lesions are often asymptomatic and are usually discovered incidentally during computed tomography or magnetic resonance imaging of the brain. Calvarial lesions can be benign or malignant. Although the majority of skull lesions are benign, it is important to be familiar with their imaging characteristics and to recognise those with malignant features where more aggressive management is needed. Clinical information such as the age of the patient, as well as the patient’s history is fundamental in making the correct diagnosis. In this article, we will review the imaging features of both common and uncommon calvarial lesions, as well as mimics of these lesions found in clinical practice.

Teaching Points

• Skull lesions are usually discovered incidentally; they can be benign or malignant.

• Metastases are the most frequent cause of skull lesions.

• Metastatic lesions are most commonly due to breast cancer in adults and neuroblastoma in children.

• Multiple myeloma presents as the classic “punched out” lytic lesions on radiographs.

• Eosinophilic granuloma is an osteolytic lesion with bevelled edges.

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.

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.

Signs in Neuroradiology: A Pictorial Review

One of the major problems radiologists face in everyday practice is to decide the correct diagnosis, or at least narrow down the list of possibilities. In this context, indicative evidences (signs) are useful to recognize pathologies, and also to narrow the list of differential diagnoses. Despite classically being described for a single disease, or a closely related family of disorders, most indications are not restricted exclusively to their traditional definition. Therefore, using signs for prognosis requires knowledge of the mechanism of their appearance, and which pathologies they are observed in. In this study, we demonstrate some of the more common and useful neuroradiologic signs with relevant images, and discuss their use in differential diagnosis.

Skull Base Tumors and Tumor-Like Lesions: A Pictorial Review

A number of tumors and tumor-like non-neoplastic lesions with different cell types on histology occur in the skull base. A wide variety in disease and lesion appearance often complicates the process of radiological diagnosis. The main role of radiographic imaging is the detection and characterization of skull base lesions, with evaluation of the extent of invasion or preservation of adjacent critical organs. Evaluation of the skull base anatomy and surgical planning by using image guidance are also important for surgeons. Computed tomography (CT) and magnetic resonance (MR) imaging are the preferred modalities for the evaluation of skull base lesions. CT and MR are used for lesion detection, tissue characterization and assessment of neurovascular and bone involvement by the lesions. Both modalities provide useful information, one sometimes of greater value than the other. T1-weighted MR imaging is useful in detecting skull base lesions, typically surrounded by abundant fatty bone marrow. T2-weighted MR imaging is generally useful for tumor tissue characterization. CT surpasses MR imaging in evaluating intratumoral calcification and bone destruction or hyperostosis. To date, imaging features have been well-reported in individual skull base tumors; however, correct diagnosis by imaging alone still presents a challenge. Knowledge of clinical issues and awareness of variants of skull base tumors are of help in making a diagnosis. The purpose of this article is to review pertinent clinical issues, typical imaging appearances and certain imaging variations of common skull base lesions.

Computed Tomography in Craniofacial Fibrous Dysplasia: A Case Series with Review of Literature and Classification Update

Introduction:

Fibrous dysplasia (FD) is a fibroosseous lesion of the osseous structures of the body. It is not a commonly reported lesion yet it is considered as an important lesion which can affect the maxillofacial region as well. As a result, it can cause deformity of the jaw bones which can further lead to severe facial asymmetry. Craniofacial fibrous dysplasia (CFD) is one of the subtypes of FD that can affect the bones of the craniofacial complex, including the mandible and maxilla. It can also present as facial asymmetry and can be investigated with the help of Maxillofacial Radiology and Imaging. The radiographic findings may vary according to the extent and degree of the disease. Although conventional radiographs provide a good clue regarding the lesion, advanced maxillofacial imaging is capable of providing detailed extent of the disease. Furthermore the classification of CFD is not very clear in the literature.

Case Report:

This particular paper attempts to document and report the CT appearance of CFD with an attempt to propose a better classification system for the same. Four different patients are reported which presented with FD with involvement of bones of craniofacial region. Working diagnosis of CFD was made with the help of clinical features as well as with radiographic assessment. Advanced imaging included CT scan of the lesions. The article highlights the importance of computed tomography in diagnosis as well as assessment of extent of the disease.

Conclusion:

It can be concluded that the Dental professionals must be aware regarding the different radiographic appearances of CFD. Advanced imaging modality like CT can provide with exact diagnosis as well as extent of the lesions like FD. Further collaboration of researchers is required to incorporate this proposed change in classification of CFD.

Might Trauma Be a Triggering Factor for Craniofacial Fibrous Dysplasia?

Fibrous dysplasia (FD) is a rare, benign disease of unclear etiology where normal bone is replaced with abnormal fibrous and weak osseous tissue. Any bone of the skeleton might be involved but skull is one of the most commonly affected sites. Fibrous dysplasia is known to be caused by a genetic mutation leading to inappropriate proliferation and differentiation of osteoblastic cells. However; it is not known whether any triggering factor exists which might contribute to this genetic mutation. The authors postulated that trauma might be a triggering factor for this disease. Trauma, as a triggering factor, has not been reported to be clearly linked to FD in the literature so far. Through this perspective; the authors report a patient of fronto-orbital fibrous dysplasia developing 6 years after a fronto-orbital skull fracture, at the same localization of the fracture line.

McCune Albright syndrome - association of fibrous dysplasia, café-au-lait skin spots and hyperthyroidism - case report

McCune–Albright syndrome is a rare sporadic disease characterized by bone fibrous dysplasia, café-au-lait skin spots and a variable association of hyperfunctional endocrine disorders. Fibrous dysplasia (FD), which can involve the craniofacial, axial, and appendicular skeleton, may range from an isolated, asymptomatic monostotic lesion to a severe disabling polyostotic disease involving the entire skeleton. A twenty-five-year old male patient presented to our clinic with recently developed heart palpitations. He had also been feeling pain in the right femur since he was younger, without any trauma history, leading to difficulties of ambulation and limping occasionally. His physical examination revealed café-au-lait spots with irregular borders and right testicular agenesis. Laboratory findings identified hyperthyroidism with hyperparathyroidism. Radiographs of the pelvis revealed multiple lytic lesions of the right femur and magnetic resonance imaging (MRI) characterized these lesions as specific to fibrous dysplasia of the bone, without any insufficiency fracture at this level.

The association of café-au-lait skin spots with bone fibrous dysplasia, and hyperthyroidism in this patient suggested the diagnosis of McCune – Albright syndrome.

Imaging of Paranasal Sinuses and Anterior Skull Base and Relevant Anatomic Variations

This article reviews the normal anatomy and variants of the anterior skull base and sinonasal cavities that are relevant to endoscopic sinus and skull base surgery. Radiologists should be aware of sinonasal anatomy that can be impediments to surgical access and increase risk of vascular or cranial nerve injury during surgery. Imaging features of the paranasal sinuses and anterior skull base pathologies are also discussed.

Imaging of focal calvarial lesions

Focal calvarial lesions may present as a visible, palpable, or symptomatic lump; however, with increasing use of cross-sectional imaging they are often encountered as an incidental finding. Knowledge of the possible disease entities along with a structured approach to imaging is required to suggest an appropriate diagnosis and assist in management planning. Abnormalities range from common neoplastic lesions to rarer congenital conditions, benign pathologies, and calvarial defects that can mimic lesions. The aim of this article is to demonstrate the salient imaging features that may help to limit the differential diagnosis of a focal calvarial lesion.

Arrested Pneumatization of the Sphenoid Sinus on Large Field-of-View Cone Beam Computed Tomography Studies

Arrested pneumatization of the sphenoid sinus is a normal anatomical variant. The aim of this report is to define cone beam computed tomography (CBCT) characteristics of arrested pneumatization of sphenoid sinus in an effort to help differentiate it from invasive or lytic skull base lesions. Two cases are presented with incidental findings. Both studies, acquired for other diagnostic purposes, demonstrated unique osseous patterns that were eventually deemed to be anatomic variations in the absence of clinical signs and symptoms although the pattern of bone loss and remodeling was diagnosed as pneumatization of the sphenoid sinus by a panel of medical and maxillofacial radiologists following contrasted advanced imaging. It is important to differentiate arrested pneumatization of the sphenoid sinus from lesions, such as arachnoid granulations, acoustic neuroma, glioma, metastatic lesions, meningioma, or chordoma, to prevent unnecessary biopsies or exploratory surgeries that would consequently reduce treatment costs and alleviate anxiety in patients.

CT and MR Imaging in a Large Series of Patients with Craniofacial Fibrous Dysplasia

Background

In this retrospective review of patients with craniofacial fibrous dysplasia (FD), the clinical and radiological findings of CT and MR scan were analyzed.

Material/Methods

The study material included 32 patients, at 9 to 68 years of age that were directed for differential diagnostics of several disorders in the head. We recorded CT and MRI data related to the lesion number, location, sidedness, appearance, and sex of the cases with craniofacial FD.

Results

Of 32 patients involved in this study, 17 had monostotic and 15 had polyostotic involvement pattern. Bones most commonly involved by monostotic involvement in females were, in descending order, mandibular, maxillary, and sphenoid bones, while the sphenoid bone was involved the most in males. Leontiasis ossea was observed in 2 patients. Sclerotic and mixed lesion types were more common in both females and males. In T1- and T2-weighted MRI sequences, hypointensity was more common compared to hyperintensity or heterogeneous intensity. The type of enhancement of lesions was found similar after contrast medium administration.

Conclusions

In the presence of craniofacial FD during CT or MRI imaging of the head, a detailed description of FD lesions may provide an important clinical benefit by increasing radiological experience during the diagnostics of this rare disorder.

Fibrous dysplasia of the temporal bone: a review of 66 cases

OBJECTIVES/HYPOTHESIS

Fibrous dysplasia is a condition of nonmalignant osseous change and may occur in a monostotic or polyostotic pattern, the latter potentially being associated with McCune-Albright syndrome. Symptoms are highly variable and dependent upon lesion location and size.

STUDY DESIGN

Retrospective review.

METHODS

Consecutive subjects with fibrous dysplasia of the temporal bone were evaluated between 2000 and 2013 at two tertiary academic referral centers. Main outcome measures included disease presentation, diagnostic evaluation, management strategy, and outcome.

RESULTS

Sixty-six patients with fibrous dysplasia of the skull were found to have involvement of the temporal bone. The mean age at diagnosis was 25 years, 39 (59%) were female, and the mean duration of follow-up was 48 months. Six (11%) patients had monostotic disease, with the remaining 60 (89%) patients having the polyostotic form; 16 (24%) patients had McCune-Albright syndrome. The most common presenting complaint was headache (59%), followed by hearing loss (29%). The most common exam finding was cosmetic deformity (50%). Cholesteatoma (3%) and spontaneous cerebrospinal fluid fistula (1.5%) were found in a small percentage. No patients had evidence of motor cranial neuropathy by history or physical examination.

CONCLUSIONS

The clinical presentation of fibrous dysplasia involving the temporal bone is variable. A growing number of patients are diagnosed incidentally through imaging, and since most patients experience a benign course, the majority can be followed clinically without need for intervention.

LEVEL OF EVIDENCE

4.

Fibrous dysplasia and McCune-Albright syndrome: imaging for positive and differential diagnoses, prognosis, and follow-up guidelines

PURPOSE

The radiologist plays a critical role at all steps of the management of patients with fibrous dysplasia (FD) and McCune-Albright syndrome (MAS). The development of a standardized approach to the management of FD/MAS is crucial given the low incidence and multiple clinical presentations of these conditions. Our aim was to develop recommendations for bone imaging in FD/MAS management.

MATERIALS AND METHODS

The establishment of National Reference Centers in France as part of a Health Ministry program for orphan diseases has triggered the development of recommendations for the clinical management of FD/MAS. We used a well-established robust methodological approach involving an extensive literature review by a multidisciplinary working group (20 healthcare professionals) and scoring by a peer-review group (20 healthcare professionals different from the 20 previous ones). There were four phases: a systematic literature review, drafting of initial recommendations, peer-review of this initial draft, and drafting of the final recommendations.

RESULTS

Fifty-seven specific recommendations are provided as key points for the diagnosis, prognosis, and follow-up of patients with FD/MAS. Issues of special interest are highlighted in the discussion, and areas in which future research is needed are identified.

CONCLUSION

We believe the dissemination of these recommendations within the radiology community may facilitate communication between radiologists and other healthcare providers, thereby substantially improving the management of patients with these rare but potentially disabling conditions.

'Do not touch' lesions of the skull base

Imaging of the skull base presents many challenges due to its anatomical complexity, numerous normal variants and lack of familiarity to many radiologists. As the skull base is a region which is not amenable to physical examination and as lesions of the skull base are generally difficult to biopsy and even more difficult to operate on, the radiologist plays a major role in directing patient management via accurate image interpretation. Knowledge of the skull base should not be limited to neuroradiologists and head and neck radiologists, however, as the central skull base is routinely included in the field of view when imaging the brain, cervical spine, or head and neck with computed tomography or magnetic resonance imaging, and hence, its nuances should be familiar to general radiologists as well. We herein review the imaging findings of a subcategory of lesions of the central skull base, the 'do not touch' lesions.

Surgical treatment of craniofacial fibrous dysplasia in adults

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

An analysis of the alleged skeletal remains of Carin Göring

In 1991, treasure hunters found skeletal remains in an area close to the destroyed country residence of former Nazi leader Hermann Göring in northeastern Berlin. The remains, which were believed to belong to Carin Göring, who was buried at the site, were examined to determine whether it was possible to make a positive identification. The anthropological analysis showed that the remains come from an adult woman. The DNA analysis of several bone elements showed female sex, and a reference sample from Carin's son revealed mtDNA sequences identical to the remains. The profile has one nucleotide difference from the Cambridge reference sequence (rCRS), the common variant 263G. A database search resulted in a frequency of this mtDNA sequence of about 10% out of more than 7,000 European haplotypes. The mtDNA sequence found in the ulna, the cranium and the reference sample is, thus, very common among Europeans. Therefore, nuclear DNA analysis was attempted. The remains as well as a sample from Carin's son were successfully analysed for the three nuclear markers TH01, D7S820 and D8S1179. The nuclear DNA analysis of the two samples revealed one shared allele for each of the three markers, supporting a mother and son relationship. This genetic information together with anthropological and historical files provides an additional piece of circumstantial evidence in our efforts to identify the remains of Carin Göring.

Fibrous dysplasia of the sinonasal tract and adjacent skull base

PURPOSE OF REVIEW

Fibrous dysplasia is a rare condition characterized by replacement of normal bone by fibro-osseous connective tissue exhibiting varying degrees of osseous metaplasia, which can affect the craniofacial complex. This article reviews the recent literature with the intent to highlight the innovative information that has contributed to elucidate the pathophysiology, diagnostic criteria, and treatment principles of the disease.

RECENT FINDINGS

A mutation in the GNAS1 gene on chromosome 20 has been identified as the molecular hallmark of fibrous dysplasia. This finding is not present in ossifying fibroma, which has been traditionally included in differential diagnosis. The concept that asymptomatic patients do not require surgical treatment has been reinforced by a meta-analysis specifically addressing the issue of optic nerve decompression.

SUMMARY

A diagnosis of fibrous dysplasia can be achieved by combined assessment of clinical, radiologic, and pathologic findings. There is general agreement that, when the disease is not associated with symptoms, partial or radical resection is not indicated, but patients do require periodic radiologic evaluations. There is, however, an absolute need for prospective studies to identify factors predicting the possible late growth of the disease and to investigate the efficacy and side-effects of pharmacological treatment with biphosphonates.

Imaging appearance of bone tumors of the maxillofacial region

This paper reviews the imaging appearance of benign and malignant bone tumors of the maxillofacial region. A benign bone tumor commonly appears as a well circumscribed lesion. The matrix of the tumor may be calcified or sclerotic. Malignancies often display aggressive characteristics such as cortical breakthrough, bone destruction, a permeative pattern and associated soft-tissue masses. Computed tomography scan is an excellent imaging modality for accurate localization of the lesion, characterization of the tumor matrix and detection of associated osseous changes such as bone remodeling, destruction or periosteal reaction. Magnetic resonance imaging is of limited value in the evaluation of maxillofacial bone tumors.

Different imaging techniques in the head and neck: Assets and drawbacks

In this review, the gold standard imaging techniques for the head and neck and the latest upcoming techniques are presented, by comparing computed tomography (CT), magnetic resonance imaging and positron emission tomography-CT, as well as ultrasound, depending on the examined area. The advantages and disadvantages of each examination protocol are presented. This article illustrates the connection between the imaging technique and the examined area. Therefore, the head and neck area is divided into different sections such as bony structures, nervous system, mucous membranes and squamous epithelium, glandular tissue, and lymphatic tissue and vessels. Finally, the latest techniques in the field of head and neck imaging such as multidetector CT, dual-energy CT, flash CT, magnetic resonance angiography, spectroscopy, and diffusion tensor tractography using 3 tesla magnetic resonance are discussed.