Skull Vault Lesions: A Review

A unique presentation of an osteolytic chronic lymphocytic leukemia/small lymphocytic lymphoma as a helmet-shaped tumor

Background

Cranial vault lymphomas (CVLs) are rare skull lesions, mostly caused by diffuse large B-cell lymphoma, a subtype of non-Hodgkin lymphoma (NHL). Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) extremely rarely causes cranial vault lesions. Herein, we report a case of a CLL/SLL causing a unique and extensive cranial vault lesion with a striking presentation of a helmet-shaped tumor, whose treatment with ibrutinib led to full bone regeneration.

Case Description

A 63-year-old woman was admitted to our hospital for the continuation of treatment of CLL/SLL, which presented with hypercalcemia, generalized lymphadenopathy, and osteolytic lesions of Th10, Th11, and L2 vertebrae. An initial head computed tomography (CT) scan, performed due to psychomotor impairment, showed an extensive CVL. Despite therapy, a control CT scan showed progression of the CVL-shaped like a helmet, destroying the occipital, both parietal and a part of the frontal bone, with the effacement of the external table and somewhat preserved internal table. Successful therapy with ibrutinib led to full bone regeneration.

Conclusion

Striking CVL presentations like the extensive permeative dissolution of the whole cranium rarely occur, especially in otherwise indolent types of NHL. Nevertheless, full bone regeneration and recovery are possible with modern treatment options, given adequate analysis is obtained beforehand. In case of a discrepancy between core-needle biopsy or fine-needle aspiration findings and the clinical picture, a surgical biopsy is warranted.

Imaging approach to pediatric calvarial bulges

Palpable calvarial lesions in children may require multi-modality imaging for adequate characterization due to non-specific clinical features. Causative lesions range from benign incidental lesions to highly aggressive pathologies. While tissue sampling may be required for some lesions, others have a typical imaging appearance, and an informed imaging approach facilitates diagnosis. This review illustrates imaging findings of common and clinically important focal pediatric calvarial bulges to aid the radiologist in narrowing the differential diagnosis and directing appropriate referral. We focus on birth-related lesions, congenital abnormalities, and modeling disturbances (i.e., those that produce a change in calvarial contour early in development), normal variants, and neoplastic lesions with their mimics.

Botulinum toxin: a new differential diagnosis for a lytic bone lesion

BACKGROUND

Botulinum toxin, produced by the Gram-positive anaerobe Clostridium botulinum, is composed of seven antigenic subtypes (A, B, C, D, E, F, and G). Currently, only Botulinum toxin type A, commonly referred to as "Botox," is approved for clinical use, given its relatively safe clinical profile. Botulinum toxin type A has a wide range of therapeutic indications, including treatment for dystonia, migraine headache, neurogenic bladder, and large muscle spastic disorders. However, the toxin is most widely known for its cosmetic effects in treating wrinkles and facial lines.

CASE PRESENTATION

This article describes a 62-year-old Caucasian female who presented for investigation and workup of an isolated lytic lesion of her frontal bone a few weeks after administration of botulinum toxin injection into the corresponding site in the frontalis muscle. This presented as a large, palpable, painless forehead lump causing significant psychological distress. After no neoplastic cause for the lesion was found and histopathology was performed, our researchers concluded that the most likely explanation was that the bony lytic lesion resulted from inadvertent injection of the "Botox" neurotoxin through the intended target muscle and into the cortex of the underlying bone.

CONCLUSIONS

Our search of the literature failed to identify any previous cases of this occurring. However, as the popularity of this cosmetic procedure only increases, we believe that this represents an important possible differential for isolated lytic lesion after administration of "Botox" injection.

Surgical Proposition of a Slow-Growing Calvarial Exostosis in a Female Patient With a Congenital Iris Cyst of the Anterior Chamber and Mandibular Tori

We present an unusual case of a woman in her early 50s with a slow-growing calvarial exostosis. Exostoses are bony spurs or osteomas extending outward beyond a bone's surface and may be benign or malignant. Calvarial exostoses are a less common bone tumor that can occur in the population. We present a case of a rare, slow-growing calvarial exostosis with a combination of mandibular tori and a congenital iris cyst. We discuss differentials of this exostosis and different syndromes that may cause it such as hereditary multiple exostoses and Gardner syndrome. The current article aims to spread awareness of this atypical presentation of exostoses and present our institution's surgical proposition for removing a calvarial exostosis to obtain a further histological analysis of its composition. As these masses may commonly be benign, a definitive diagnosis cannot be made through imaging alone to rule out more threatening conditions. We have addressed radiological findings and diagnostic and treatment options offered to the patient. The patient decided not to move forward with removing the mass and would continue to monitor and return should she notice any unusual or acute changes.

Imaging of pediatric skull lytic lesions: A review

Skull lesions in pediatric population are common findings on imaging and sometimes with heterogeneous manifestations, constituting a diagnostic challenge. Some lesions can be misinterpreted for their aggressiveness, as with larger lesions eroding cortical bone, containing soft tissue components, leading to excessive and, in some cases, invasive inappropriate etiological investigation. In this review, we present multiple several conditions that may present as skull lesions or pseudolesions, organized by groups (anatomic variants, congenital and development disorders, traumatic injuries, vascular issues, infectious conditions, and tumoral processes). Anatomic variants are common imaging findings that must be recognized by the neuroradiologist. Congenital malformations are rare conditions, such as aplasia cutis congenita and sinus pericranii, usually seen at earlier ages, the majority of which are benign findings. In case of trauma, cephalohematoma, growing skull fractures, and posttraumatic lytic lesions should be considered. Osteomyelitis tends to be locally aggressive and may mimic malignancy, in which cases, the clinical history can be the key to diagnosis. Vascular (sickle cell disease) and tumoral (aneurismal bone cyst, eosinophilic granuloma, metastases) lesions are relatively rare lesions but should be considered in the differential diagnosis, in the presence of certain imaging findings. The main difficulty is the differentiation between the benign and malignant nature; therefore, the main objective of this pictorial essay is to review the main skull lytic lesions found in pediatric age, describing the main findings in different imaging modalities (CT and MRI), allowing the neuroradiologist greater confidence in establishing the differential diagnosis, through a systematic and simple characterization of the lesions.

Pediatric focal calvarial lesions: an illustrated review

Focal skull lesions in children can be diagnostically challenging with a wide variety of potential etiologies. Understanding the diverse pathologies and recognizing their associated clinical and imaging characteristics is crucial for accurate diagnosis and appropriate treatment planning. We review pertinent anatomy of the scalp and calvarium and review different pathologies that can present with focal skull lesions in pediatric patients. These include neoplastic, non-neoplastic tumor-like, congenital, post traumatic, and vascular-associated etiologies. We review the key clinical and imaging features associated with these pathologies and present teaching points to help make the correct diagnosis. It is important for radiologists to be aware of the common and rare etiologies of skull lesions as well as the clinical and imaging characteristics which can be used to develop an accurate differential to ensure a timely diagnosis and initiate appropriate management.

An algorithmic clinicoradiological approach to paediatric cranial vault lesions: distinguishing normal variants from pathologies

Lesions of the paediatric cranial vault are diverse both in their presentation and aetiology. As such, they pose a diagnostic challenge to the paediatric neurosurgeon and neuroradiologist. In this article, we delineate the spectrum of paediatric calvarial pathology into four distinct groups: (1) lytic lesion(s); (2) focal sclerotic lesion(s); (3) diffuse cranial vault sclerosis; and (4) abnormal shape of the cranial vault. It is our aim that this more pragmatic, algorithmic approach may mitigate diagnostic uncertainty and aid the more accurate diagnosis of paediatric calvarial lesions.

External auditory canal and middle ear tumors: characterization by morphology and diffusion features on CT and MRI

PURPOSE

To explore the value of morphology and diffusion features on CT and MRI in the characterization of external auditory canal and middle ear tumors (EAMETs).

METHODS

Forty-seven patients with histologically proved EAMETs (23 benign and 24 malignant) who underwent CT and MRI were retrospectively analyzed in this study. CT and MRI characteristics (including size, shape, signal intensity, border, enhancement degree, and bone changes) and apparent diffusion coefficient (ADC) value were analyzed and compared between benign and malignant EAMETs. Logistic regression, receiver operating characteristic (ROC) curve, and Delong test were performed to assess the diagnostic performance.

RESULTS

Compared with benign tumors, the malignant EAMETs are characterized by irregular shape, ill-defined border, invasive bone destruction, and intense enhancement (all p < 0.05). There were no significant differences on the size and signal intensity between benign and malignant tumors. The ADC value of malignant tumors were (879.96 ± 201.15) × 10^-6 mm²/s, which was significantly lower than benign ones (p < 0.05). Logistic regression demonstrates the presence of ill-defined margin, invasive bone destruction, and low ADC value (≤ 920.33 × 10^-6 mm²/s) have significant relationship with malignant EAMETs. The combination of characterization by morphology and diffusion features on CT and MRI can further improve the diagnostic efficiency when compared with morphology and diffusion features alone (both p < 0.05).

CONCLUSION

Some CT and MRI characteristics are helpful in identifying malignant EAMETs from benign ones (especially ill-defined margin, invasive bone destruction, and low ADC value), and the combination of morphology and diffusion features on CT and MRI has best diagnostic efficiency for discriminating these two entities.

Comparison of computed tomography and magnetic resonance imaging in evaluation of skull lesions

Background

Computed tomography (CT) and magnetic resonance imaging (MRI) have been incorporated into the basic imaging tools for evaluation of skull lesions. Despite the known advantages and disadvantages of CT and MRI in various aspects of evaluating skull lesions, it is not always feasible to perform both CT and MRI in evaluation of the same patient. The purpose of this study is to compare CT and MRI in evaluation of various skull lesions and to determine which imaging modality out of the two is more appropriate in evaluation of skull lesions and their characterization.

Results

There was no statistically significant difference between CT and MRI for detection of number of lesions, distribution of lesions, margins of the lesions, nature of the lesions, zone of transition, cortical breach, intralesional calcification, intralesional hemorrhage, associated soft tissue, and invasion into brain parenchyma (p value > 0.05 in all these parameters). Dural involvement was picked up better on MRI as compared to CT (p value 0.031). Another advantage of MRI over CT was better characterization of lesions by diffusion weighted imaging.

Conclusion

CT and MRI are equally efficient in providing adequate diagnostic information in various skull lesions and each of them can be used independent of the other to characterize and diagnose the lesions of skull. The slight advantage of MRI over CT is detection of dural involvement.

Metastatic cancer and endentulism: Exploring comorbidity to assist with differential diagnosis in a case from Vico nel Lazio (Fr, Italy), 13th-15th century CE

OBJECTIVE

To differentially diagnose cranial lesions noted on a medieval skeleton and explore the importance of comorbidity.

MATERIALS

A skull of an adult female with osteolytic and osteoblastic lesions, edentulism, and an ectopic tooth from an ossuary of the Church of Santa Maria in Vico del Lazio, Frosinone Italy, dating to the Middle Ages.

METHODS

Macroscopic observations of the remains, CT scan, and differential diagnosis was undertaken.

RESULTS

A diagnosis of metastatic cancer (potentially breast cancer) or metastatic neuroblastoma (NBL) is offered.

CONCLUSIONS

Considering the noted comorbidities, this case might represent a rare case of metastatic neuroblastoma.

SIGNIFICANCE

The exploration of comorbidity, in this case the presence of metastatic carcinoma and edentulism, has tremendous potential to expand our knowledge about cancer in the past.

LIMITATIONS

Lack of postcranial elements.

SUGGESTIONS FOR FURTHER RESEARCH

Clinical and paleopathological investigation of comorbidity in modern and archeological populations to develop an evolutionary perspective on the presence of cancer in the past.

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.

Intraosseous metaplastic meningioma: A case report

Metaplastic meningioma is a rare World Health Organization Grade I meningioma subtype, accounting for 0.2%-1.6% of all meningiomas. Primary extradural meningiomas represent less than 2% of all meningiomas, with intraosseous meningioma as a subtype of primary extradural meningiomas. Herein, we report the case of a 65-year-old male presenting with headache. His computed tomography scans showed an osteolytic left parietal bone mass, and magnetic resonance imaging revealed hyperintense dots in the mass on T1-weighted images. The mass was then resected and diagnosed on histopathological examination as an intraosseous metaplastic meningioma.

Calcified Pseudoneoplasm of the Neuraxis

Calcified pseudoneoplasms of the neuraxis are extremely rare non-neoplastic lesions that can exist anywhere in the CNS. Although benign, the lesions can cause substantial neurologic symptoms, typically related to mass effect on adjacent structures. Calcified pseudoneoplasms of the neuraxis can also mimic other entities such as calcified oligodendrogliomas and meningiomas. Nevertheless, the lesions can usually be strongly suggested at the time of imaging due to a number of fairly unique imaging characteristics. Here, the clinical presentation of a patient with a posterior fossa calcified pseudoneoplasm of the neuraxis is described, along with its imaging and pathologic features.

Giant Calcified Cavernous Hemangioma Managed with Modified Double Concentric Craniotomy

Giant calcified cavernous hemangioma is uncommon, and calvarial invasion with intracranial extension and dural breach is rare. Radiological resemblance to lesions like meningioma is unreported. Surgical excision of such lesions is technically challenging. A 35-year-old female presented with recurrent generalized tonic-clonic seizures for 2 years. Imaging suggested a highly vascular lesion arising from the skull, mimicking intraosseous meningioma, sarcoma, metastases, and so on. Double concentric craniotomy was done with lifting of bones separately around sinuses with radial cuts of dura to visualize tumor-cortical interface to safeguard neurovascular structures, and complete excision was achieved. Histopathology was suggestive of calcified cavernous hemangioma. The patient was asymptomatic at 1 year of follow-up.Differentiating angiomatous and intraosseous meningioma from calcifying giant hemangioma and other mimicking lesions may be difficult on imaging. Modified double concentric craniotomy, although used uncommonly, can be a useful technique safeguarding the neurovascular structures in its proximity.

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.

Calvarial Lesions: A Tertiary Centre's Experience Over Fifteen Years

Background

The human calvaria harbors a variety of pathology and majority of them are incidentally noticed as painless swelling. The aim of the present study is to describe the histopathological subtypes of calvarial lesions, their management and factors affecting their surgical outcome at a tertiary care referral center.

Material and Methods

All patients who underwent excision of the calvarial lesions over the last 15 years (from January 2005 to July 2019) were included in this study. Patients having calvarial pathology of infective origin and recurrent lesions were excluded. Any patient with multiple calvarial lesions who have been operated more than one time for same histopathological diagnosis was counted as one patient. We studied Karnofsky Performance Status (KPS) scores and radiological changes at 3-month follow up.

Results

Total 65 patients were recruited in this retrospective observational study. The median age of patients in the study was 29 years (range: 8 years to 68 years). Fibrous dysplasia 20 (30.7%) was the commonest lesion while metastatic thyroid carcinoma 3 (4.6%) was the most common malignant pathology. Complete excision was performed in 51 (78.5%) of patients while in 14 (21.5%) cases, subtotal or near total decompression were achieved. After three months of surgery, there was significant improvement in the KPS score (P < 0.00001). Duration of follow up ranges from 6 months to 5 years with 4 mortality in the study.

Conclusions

Most of the calvarial tumors were benign and surgically addressable. The malignant lesions were scattered with diverse underlying pathology and required individualized holistic approach.

Imaging Review of Pediatric Benign Osteocytic Tumors and Latest Updates on Management

Pediatric benign osteocytic tumors include osteoma, enostosis, osteoid osteoma, and osteoblastoma. In pediatric populations, benign bone tumors are more common than malignancies. Benign osteocytic tumors may have a unique clinical presentation that helps narrow the differential diagnosis. A systemic imaging approach should be utilized to reach the diagnosis and guide clinicians in management. Radiographs are the most prevalent and cost-effective imaging modality. Cross-sectional imaging can be utilized for tissue characterization and for evaluation of lesions involving complex anatomical areas such as the pelvis and spine. Computed Tomography (CT) is the modality of choice for diagnosis of osteoid osteoma. CT scan can also be utilized to guide radiofrequency ablation, which has been found to be highly effective in treating osteoid osteoma and osteoblastoma. Enostosis is a no-touch lesion. Osteoma is commonly located in the paranasal sinuses. Osteoma needs an excision if it causes complications due to a mass effect.

Skull Imaging-Radiographs and CT revisited

Although rare, skull vault lesions include a vast array of pathology encompassing infection, benign, and malignant bone tumors. Given the large range of potential diagnoses, it is crucial to identify imaging features to differentiate one from another, ensuring early diagnosis. Radiographs are still valuable in modern radiology but have largely been superseded by computed tomography (CT) due to its high spatial resolution. Both are especially important in developing countries where access to magnetic resonance imaging (MRI) may be limited.There are currently several publications outlining imaging appearances of skull vault lesions. However, the majority of literature is dated, with the last dedicated textbook published in 1980 (Principles of X-ray diagnosis of the skull). Despite overlapping features, a few lesions have "aunt minnie," type classical characteristics, which we will highlight. Most vault lesions also appear as a spectrum depending on location and the exact stage of the disease. A small subset within each disease entity also has atypical features not widely discussed in the current literature. In this pictorial review, we hope to focus on radiographic and CT imaging appearances to help differentiate between various skull vault lesions.

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.

A unique case of multiple calvarial hemangiomas with one large symplastic hemangioma

BACKGROUND

Symplastic hemangioma is a benign superficial abnormal buildup of blood vessels, with morphological features which can mimic a pseudo malignancy. A few cases have been reported in the literature. We report here, a unique case of calvarial symplastic hemangioma, which is the first case in the calvarial region.

CASE PRESENTATION

A 29-year-old male patient, with a left occipital calvarial mass since childhood, that gradually increased in size with age, was associated with recurrent epileptic fits controlled by Levetiracetam (Keppra), with no history of trauma. He presented to the emergency room with a recent headache, vomiting, frequent epileptic fits and a decrease in the level of consciousness 1 day prior to admission. A CT scan showed three diploic, expansile, variable sized lytic lesions with a sunburst appearance; two that were biparietal, and one that was left occipital, which were all suggestive of calvarial hemangiomas. However, the large intracranial soft tissue content, within the hemorrhage of the occipital lesion was concerning. The patient had refused surgery over the years; however, after the last severe presentation, he finally agreed to treatment. The two adjacent, left parietal and occipital lesions were treated satisfactorily using preoperative embolization, surgical resection, and cranioplasty. Histopathology revealed cavernous hemangiomas, in addition to symplastic hemangioma (pseudo malignancy features) on top at the occipital lesion. The right parietal lesion was not within the surgical field; therefore, it was left untouched for follow-up.

CONCLUSIONS

Histopathology and radiology examinations confirmed the diagnosis as symplastic hemangioma, on top of a pre-existing cavernous hemangioma. To the best of our knowledge, this is the first case of a calvarial symplastic hemangioma, which we report here.

Eosinophilic Granuloma of the Skull Presenting as Non-Traumatic Extradural Haematoma in Children

Cranial extradural haematoma (EDH) is a neurosurgical emergency that can be caused by traumatic or non-traumatic causes with the former being more prevalent. Non-traumatic causes are variable and can include infection, vascular malformation and haematological disorders. This paper will address an extremely rare non-traumatic cause of EDH. More specifically, eosinophilic granuloma (EG), the localized form of Langerhans histiocytosis, may involve the skull and has rarely been reported to present with EDH. The case that will be presented is that of a three-year-old male patient, who presented with progressive vomiting and drowsiness, associated with left parietal swelling. CT scan of the brain showed an extradural haematoma and an osteolytic parietal lesion. He underwent emergent craniectomy, evacuation of the haematoma and dura resection as the lesion was infiltrating the dura. Histopathological examination of the dura and the bone edges showed eosinophilic granuloma (EG). The mechanism of a haemorrhage in this situation is poorly understood and the literature is extremely scarce. In conducting a thorough literature review, only 11 case reports of EG causing non-traumatic EDH were found. The details of these 11 cases will be reviewed and discussed in this paper, in addition to our illustrative case.

Bony lesions of cranium and spine: A study of 123 cases

CONTEXT

Bony lesions involving the cranium and spine have a wide range of etiologies, ranging from congenital, traumatic, inflammatory, to neoplastic.

AIM

The aim was to analyze the histological spectrum of various bony lesions of cranium and spine received as biopsies from the neurosurgery department in our hospital.

MATERIALS AND METHODS

There were 123 cases of bony lesions of cranium and spine diagnosed over a period of 5 years during 2015-2019 in the neuropathology laboratory. These cases were studied retrospectively.

RESULTS

Out of the total 123 cases of bony lesions analyzed, 75 affected the cranium and 48 affected the spine. Overall, neoplastic lesions (83) were more frequent than the nonneoplastic lesions (40). In the cranium, neoplastic lesions (66/75) outnumbered the nonneoplastic ones (9/75), whereas in the spine, nonneoplastic lesions (31/48) were more common. Chordoma (40/83) was the most common neoplasm, whereas tuberculous osteomyelitis (30/40) was the most common nonneoplastic lesion encountered. Majority of the patients were adult males aged between 21 and 50 years. Rare lesions such as spinal osteochondroma, poorly differentiated neoplasm metastatic to the cervical spine from a primary salivary gland neoplasm, spinal metastasis of a glioblastoma, and intraosseous meningioma of cranium were recorded.

CONCLUSIONS

The study provides epidemiological information regarding the incidence and nature of bone lesions of the spine and cranium.

Imaging of skull vault tumors in adults

The skull vault, formed by the flat bones of the skull, has a limited spectrum of disease that lies between the fields of neuro- and musculoskeletal radiology. Its unique abnormalities, as well as other ubiquitous ones, present particular features in this location. Moreover, some benign entities in this region may mimic malignancy if analyzed using classical bone-tumor criteria, and proper patient management requires being familiar with these presentations. This article is structured as a practical review offering a systematic diagnostic approach to focal calvarial lesions, broadly organized into four categories: (1) pseudolesions: arachnoid granulations, meningo-/encephaloceles, vascular canals, frontal hyperostosis, parietal thinning, parietal foramina, and sinus pericrani; (2) lytic: fibrous dysplasia, epidermal inclusion and dermoid cysts, eosinophilic granuloma, hemangioma, aneurysmal bone cyst, giant cell tumor, metastasis, and myeloma; (3) sclerotic: osteomas, osteosarcoma, and metastasis; (4) transdiploic: meningioma, hemangiopericytoma, lymphoma, and metastasis, along with other less common entities. Tips on the potential usefulness of functional imaging techniques such as MR dynamic susceptibility (T2*) perfusion, MR spectroscopy, diffusion-weighted imaging, and PET imaging are provided.

Utilization of contrast-enhanced ultrasound in the evaluation of craniofacial osseous lesions: A case report

A 14-year-old boy undergoing brain MRI had an incidental avidly enhancing lobulated lesion in the left superolateral orbital rim with associated cortical erosion. Apart from Contrast-enhanced Magnetic Resonance Imaging (MRI), and Computed Tomography (CT), Contrast-Enhanced Ultrasound (CEUS) was obtained prior to a biopsy. It provided additional information about the microvasculature and an orbital biopsy was subsequently performed through an upper eyelid crease incision with minimal blood loss and no postoperative complications. Histopathological examination revealed features which were compatible with the diagnosis of LCH. The authors propose that CEUS may be considered as an adjunct and possibly alternative imaging modality for the evaluation of craniofacial osseous lesions, especially in the orbital region (due to the known radio-sensitivity of the eyes) and in pediatric patients, to minimize the risk of ionizing-radiation exposure.

Large solitary lytic skull vault lesions in adults: radiological review with pathological correlation

The diagnosis of a large solitary lytic skull vault lesion in adults is a challenge due to variable aggressiveness and overlapping features. The purpose of this article is to demonstrate the use of an imaging approach to narrow the differential diagnosis when a large solitary lytic skull vault lesion is encountered. The initial imaging assessment using computed tomography (CT) is invaluable in determining lesion aggressiveness based on bony margins and skull tables involvement. Further assessment with magnetic resonance (MR) imaging including diffusion weighted imaging (DWI) aids in soft tissue characterization. We present cases of large solitary lytic skull vault lesions in adults, emphasizing on salient and atypical imaging features, with pathological correlation for better understanding of the disease processes that underlie the imaging features.

A Large Mass Mimicking Calcified Hematoma of the Skull Showing Involvement of Myeloma Cells and a Good Response to Irradiation

Patients with multiple myeloma often show skull bone involvement, although in most cases this is manifested as skull erosion and large masses develop only rarely. Here we report a patient who presented with a large cranial mass mimicking a subdural hematoma with calcification. The tumor shrunk with 37.5 Gy of focal irradiation in 15 fractions after biopsy. After irradiation the patient was treated with Bortezomib but died because of adverse events. The differential diagnosis of lenticular lesion of the skull and treatment strategy for large skull mass with myeloma cells are discussed.

Benign and malignant skull-involved lesions: discriminative value of conventional CT and MRI combined with diffusion-weighted MRI

BACKGROUND

Little is known about the value of computed tomography (CT) and magnetic resonance imaging (MRI) combined with diffusion-weighted imaging (DWI) in distinguishing malignant from benign skull-involved lesions.

PURPOSE

To evaluate the discriminative value of DWI combined with conventional CT and MRI for differentiating between benign and malignant skull-involved lesions.

MATERIAL AND METHODS

CT and MRI findings of 58 patients with pathologically proven skull-involved lesions (43 benign and 15 malignant) were retrospectively reviewed. Conventional CT and MRI characteristics and apparent diffusion coefficient (ADC) value of the two groups were evaluated and compared. Multivariate logistic regression and receiver operating characteristic (ROC) curve analyses were performed to assess the differential performance of each parameter separately and together.

RESULTS

The presence of cortical defects or break-through and ill-defined margins were associated with malignant skull-involved lesions (both P < 0.05). Malignant skull-involved lesions demonstrated a significantly lower ADC (P = 0.016) than benign lesions. ROC curve analyses indicated that a combination of CT, MRI, and DWI with an ADC ≤ 0.703 × 10^-3 mm²/s showed optimal sensitivity, while DWI along showed optimal specificity of 88.4% in differentiating between benign and malignant skull-involved lesions.

CONCLUSION

The combination of CT, MRI, and DWI can help to differentiate malignant from benign skull-involved lesions. CT + MRI + DWI offers optimal sensitivity, while DWI offers optimal specificity.

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.

Spectrum of lytic lesions of the skull: a pictorial essay

Abstract

Lytic lesions of the skull include a wide range of diseases, ranging from benign conditions such as arachnoid granulations or vascular lacunae, to aggressive malignant lesions such as lymphomas or metastases. An early and correct characterisation of the nature of the lesion is, therefore, crucial, in order to achieve a fast and appropriate treatment option. In this review, we present the radiological appearance of the most frequent lytic lesions of the skull, describing findings from different imaging modalities (plain X-rays, CT and MRI), with particular attention to diagnostic clues and differential diagnoses.

Teaching Points

• Osteolytic skull lesions may be challenging to diagnose.

• Association of different imaging techniques may aid image interpretation.

• Clinical information and extensive knowledge of possible differential diagnoses is essential.

• Some osteolytic tumours, although benign, may present as locally aggressive lesions.

• Malignant lesions require accurate staging, followed by variable treatment approaches.