Spectrum of lytic lesions of the skull: a pictorial essay

A calvarial osteolytic lesion of probable vascular origin in a Maya juvenile from the Classic Period ( 250-900 CE)

OBJECTIVE

This case study evaluates a focal osteolytic lesion in the right sulcus sinus transversi of an isolated os occipitale.

MATERIALS

The os occipitale is from a juvenile from the Cueva de Sangre at the Classic Period (250-900 CE) site of Dos Pilas, Guatemala METHODS: The lesion was examined macroscopically, microscopically, and radiographically.

RESULTS

The oval lesion has a well-circumscribed margin, endocranial origin, and involves cortical destruction of the inner and outer tables. Subperiosteal bone reaction around the lesion is present on the ectocranial surface. Skeletal evidence of increased vascularity, diploë expansion, and perimortem fracture near the lesion are not observed.

CONCLUSIONS

The lesion appears to reflect a response to the presence of an expansile process that has caused pressure erosion. The anatomical location of the lesion and the endocranial origin suggest a probable vascular anomaly, such as a vascular malformation.

SIGNIFICANCE

This case study represents one of the few bioarchaeological evaluations of probable vascular anomaly in a juvenile. As such, it expands our knowledge about vascular anomalies in the past and provides a comparative and core reference for guiding future paleopathological investigations on cranial osteolytic lesions.

LIMITATIONS

The skeletal assemblage is commingled and fragmentary preventing the assessment of the distribution of lesions across the skeleton.

SUGGESTIONS FOR FUTURE RESEARCH

Further scrutiny of bioarchaeological collections is needed to better understand the distribution of vascular anomalies in the past.

Pediatric orbital lesions: bony and traumatic lesions

Orbital pathologies can be broadly classified as ocular lesions, extraocular soft-tissue pathologies (non-neoplastic and neoplastic), and bony and traumatic lesions. In this paper, we discuss the key imaging features and differential diagnoses of bony and traumatic lesions of the pediatric orbit and globe, emphasizing the role of CT and MRI as the primary imaging modalities. In addition, we highlight the adjunctive role of ocular sonography in the diagnosis of intraocular foreign bodies and discuss the primary role of sonography in the diagnosis of traumatic retinal detachment.

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.

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.

Prevalence of intra-osseous veins and venous lakes in the posterior skull base on 3T MRI

BACKGROUND

Intra-osseous vessels are normal anatomic structures in the calvarium and skull base. On imaging, these structures-particularly venous lakes-can mimic pathologic abnormalities. This study sought to assess the prevalence of veins and lakes in the skull base on MRI.

MATERIALS AND METHODS

A retrospective review was completed of consecutive patients that underwent contrast-enhanced MRI imaging of the internal auditory canals. The clivus, jugular tubercles, and basio-occiput were assessed for the presence of both intra-osseous veins (serpentine and/or branching vessels) and venous lakes (well-circumscribed round or oval enhancing structures). Vessels in the adjacent synchondroses major foramina were excluded. Three board-certified neuroradiologists performed independent blinded reviews, with discrepancies agreed upon by consensus.

RESULTS

96 patients were included in this cohort (58.3% female). Mean age was 58.4 years (range = 19-85). At least one intra-osseous vessel was identified in 71 (74.0%) patients. 67 (70.0%) had at least one skull base vein, and 14 (14.6%) had at least one venous lake. Both vessel subtypes were observed in 8.3% of patients. Vessels were more commonly observed in women, though this did not reach statistical threshold (p = 0.56). Age was not associated with the presence of vessels (0.59) or vessel location (p values ranged from 0.44-0.84).

CONCLUSIONS

Intra-osseous skull base veins and venous lakes are relatively common findings on MRI. Both vascular structures should be considered normal anatomy, and care should be taken to not confuse these for pathologic entities.

Aneurysmal bone cyst of the mandible: a rare case report and literature review

Introduction and importance

Aneurysmal bone cysts (ABCs) are benign, non-neoplastic cystic lesions composed of multiple blood-filled cavities, which are separated by connective tissue septa and they constitute ~6 and 1.5% of all cases of the skull and jaws lesions, respectively.

Case presentation

Herein, the case of an 80-year-old male with a histologically confirmed diagnosis of ABC involving the body of the left mandible was presented. The patient underwent partial mandiblectomy after confirmation of the diagnosis using orthopantomography, a computed tomography scan, and a tissue biopsy. The patient was free from pain after 1-year of follow-up, and the control orthopantomography showed no evidence of recurrence. This was followed by reconstruction of the healed part of the bone with titanium plates and a piece of bone from the lateral two-thirds of the left femur and thereafter he was cosmetically well.

Clinical discussion

Patients with ABCs present with expansile and radiolucent bone lesions, which may be associated with displacement and loss of teeth due to alveolar bone erosion. Complete excision of the lesions is mandatory for the prevention of recurrence and increased morbidity.

Conclusion

ABCs that involve the jaws are extremely rare and are more likely to pose a diagnostic challenge as they are more likely to be confused clinically with other expansile radiolucent bone lesions such as ameloblastoma, osteoblastoma, and giant cell tumor among many others. Also, those with extensive bone matrix formation may sometimes be confused histologically with other bone forming tumors including osteosarcoma. Recurrence is common but it can be avoided or minimized by complete resection of the lesion.

Brown Tumour in Chronic Kidney Disease: Revisiting an Old Disease with a New Perspective

Osteitis fibrosa cystica (OFC) and Brown Tumours are two related but distinct types of bone lesions that result from the overactivity of osteoclasts and are most often associated with chronic kidney disease (CKD). Despite their potential consequences, these conditions are poorly understood because of their rare prevalence and variability in their clinical manifestation. Canonically, OFC and Brown Tumours are caused by secondary hyperparathyroidism in CKD. Recent literature showed that multiple factors, such as hyperactivation of the renin-angiotensin-aldosterone system and chronic inflammation, may also contribute to the occurrence of these diseases through osteoclast activation. Moreover, hotspot KRAS mutations were identified in these lesions, placing them in the spectrum of RAS-MAPK-driven neoplasms, which were until recently thought to be reactive lesions. Some risk factors contributed to the occurrence of OFC and Brown Tumours, such as age, gender, comorbidities, and certain medications. The diagnosis of OFC and Brown Tumours includes clinical symptoms involving chronic bone pain and laboratory findings of hyperparathyroidism. In radiological imaging, the X-ray and Computed tomography (CT) scan could show lytic or multi-lobular cystic alterations. Histologically, both lesions are characterized by clustered osteoclasts in a fibrotic hemorrhagic background. Based on the latest understanding of the mechanism of OFC, this review elaborates on the manifestation, diagnosis, and available therapies that can be leveraged to prevent the occurrence of OFC and Brown Tumours.

Metastatic Lung Adenocarcinoma: A Case of Unusual Presentation With a Skull Mass

This case report describes an uncommon presentation of lung adenocarcinoma, which appeared as a skull mass. While not the first reported case in medical literature, it is still a rare occurrence for lung adenocarcinoma to present in this manner. This report focuses on the clinical presentation and treatment of an elderly male patient who had a progressively enlarging and painful skull mass. The initial imaging revealed an about 5 cm soft tissue mass at the dorsal midline of the parietal-occipital bone. Subsequent imaging identified a lung mass, and a biopsy of the skull bone confirmed that the mass was metastatic adenocarcinoma originating from the lung. For treatment, the patient underwent occipital partial resection of the mass, followed by wire mesh cranioplasty. Chemotherapy and external beam radiotherapy were administered to alleviate symptoms and control the spread of cancer. Lung carcinoma with distant metastasis is generally associated with a poorer prognosis. However, some supporting data suggest that early detection and aggressive management play crucial roles in preventing further metastasis and improving the patient's quality of life and overall survival rate. Skull bone metastasis from lung cancer is indeed a rare phenomenon, and cases like these contribute valuable knowledge to the field. By reporting such cases, healthcare professionals can gain a better understanding of the clinical manifestations, diagnostic challenges, and appropriate management strategies for these uncommon occurrences. This case report underscores the significance of maintaining a high index of suspicion and utilizing a multimodality approach to diagnose rare instances of calvarial metastasis.

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.

Varied Clinical Presentation and Management of Calvarial Metastases

Calvarium and skull base can be affected by a variety of benign, tumor-like, and malignant processes. Skull metastases (SMs) may be located in any layer of the skull and may be incidental or present with neurological symptoms during the diagnostic workup. In the present study, we discuss the occurrence of SMs from various index malignancies and their myriad clinical presentation. This data-based study includes patients of bone metastases between June 2018 and July 2020. Patients with skull bone metastases were recognized, and location of primary site, their clinical presentation, and management strategy were noted. Ten patients with skull bone metastases were identified during this period. Four patients had skull base location with clinical manifestation as syndromes. Six patients had primary from breast cancer, three from Ewing's sarcoma, and one from lung cancer. Management varied according to the primary site and symptoms of each patient. SM, though not rare, is often diagnosed incidentally but presents diagnostic and management challenges in the patient with cancer.

Paleopathology of the skull of Santorio Santorio, father of modern clinical experimental physiology

The University of Padua (Italy) preserves the skull of Santorio Santorio, father of the modern clinical experimental physiology. A recent study performed with modern anthropological methods and medical instruments (CT scan) revealed the presence of a lobular formation in the left temporal bone, with an irregular morphology, internal bone sequestrum, a well-defined non-continuous sclerosis and both internal and external thinning of the cranial plate. Three oval depressions observed in the cranial vault, edentulism and moderate osteoarthritis of the temporomandibular joint were also investigated. The lobular formation was an epidermoid cyst and the oval depressions were the result of other cysts. The edentulism was consistent with some metabolic deficiency or disease, whilst the osteoarthritis appeared to be the result of antemortem tooth loss. This study allowed to investigate a complex and peculiar palaeopathological picture, linked to a piece of the history of the University of Padua.

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 of the Calvaria and Skull Base

A thorough understanding of the skull anatomy is of key importance to radiologists as well as specialist physicians and surgeons. We describe the anatomy of the neurocranium comprising calvaria (the skull vault) and the skull base and discuss the most common and clinically relevant anatomic variants.

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 rare case of calvarial tuberculosis from the Avar Age (8th century CE) cemetery of Kaba-Bitózug (Hajdú-Bihar county, Hungary) - Pathogenesis and differential diagnostic aspects

The aim of our paper is to present and discuss in detail the bony changes indicative of tuberculosis (TB) that were identified in a skeleton (KB67), unearthed from grave 67 of the 8th-century-CE cemetery of Kaba-Bitózug (Hungary). Furthermore, to provide the differential diagnoses of the observed alterations, with special attention to the cranial osteolytic lesions. During the macro- and micromorphological examinations of KB67, the skull revealed three small, well-circumscribed, punched-out osteolytic lesions accompanied by endocranial granular impressions, abnormal blood vessel impressions, periosteal appositions, and cortical erosion. The postcranial skeleton exhibited osteolytic lesions, cortical remodelling and erosion, and signs of hypervascularisation in the spine. Based on the differential diagnosis of the cranial osteolytic lesions and their co-occurrence with endocranial and vertebral bony changes indicative of TB, they most likely resulted from tuberculous involvement of the frontal and left parietal bones. The morphologically established diagnosis was confirmed by a PCR analysis that provided evidence for the presence of Mycobacterium tuberculosis DNA in KB67. KB67, the first reported archaeological case with calvarial TB from the present-day territory of Hungary, gives us a unique insight into the occurrence of a rare manifestation of TB in the Avar Age of the Great Plain.

Gorham Stout disease of the temporal bone with cerebrospinal fluid leak

Gorham Stout disease (GSD) is a rare disease characterized by the proliferation of endothelial lined vessels and replacement of bone by fibrous tissue. The main imaging features are progressive osteolysis and cortical resorption. Temporal bone involvement is rare but presents as a destructive bone lesion that may be misinterpreted as more common lytic processes in the pediatric population, such as infection or Langerhans cell histiocytosis. GSD of the temporal bone is associated with cerebrospinal fluid (CSF) leaks, may present with otorrhea, and can mimic other causes of ear drainage. Here, we report the clinical course, imaging features, and outcomes of a 3-year-old girl with GSD of the temporal bone presenting with CSF leak initially attributed to infection.

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.

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.

Radiologic findings that aid in the reduction of misdiagnoses of Langerhans cell histiocytosis of the bone: a retrospective study

BACKGROUND

This study aimed to identify the characteristic radiological signs for the diagnosis of Langerhans cell histiocytosis (LCH) of the bone.

METHODS

We retrospectively studied 82 cases of LCH with bone lesions confirmed by pathology. Clinical and radiological features of the patients were analyzed.

RESULTS

A total of 64 and 18 patients had single and multiple bone lesions, respectively. With regard to LCH with single bone lesions, 37.5% (24/64) of lesions were located in the skull and presented as bone destruction with or without soft tissue mass. The correct diagnosis rate of these lesions was 60.0% (9/15) in children and adolescents, but was only 22.2% (2/9) in adults. A total of 26.5% (17/64) of the solitary lesions were found in the spine. Of these, 88.2% (15/17) were located in the vertebral body and appeared to have different degrees of collapse, and 66.7% (10/15) of these lesions were correctly diagnosed. Of the unifocal lesions, 21.8% (14/64) were located in other flat and irregular bones and manifested as osteolysis. Only 21.4% (3/14) of these cases were correctly diagnosed. In total, 14.1% (9/64) of the isolated bone LCH lesions were located in the long bones. Of these, 77.8% (7/9) were located in the diaphysis and presented as central bone destruction with or without fusiform periosteal reaction and extensive peripheral edema, of which 42.9% (3/7) were correctly diagnosed before surgery or biopsy. With regard to LCH with multiple bony destructive lesions, 71.4% (10/14) of cases in children and adolescents were correctly diagnosed; however, all four cases among adults were misdiagnosed.

CONCLUSION

In all age groups, isolated diaphyseal destruction of the long bone with fusiform periosteal reaction and extensive peripheral edema, vertebra plana of the spine, and bevelled edge of skull defects accompanied by soft tissue masses strongly suggest LCH diagnosis. Moreover, the multiple bone osteolytic destruction in children and adolescents strongly suggests LCH diagnosis. Familiarity with these typical radiological signs of LCH is necessary to decrease misdiagnoses.

Benign skull and subdural lesions in patients with prior medulloblastoma therapy

PURPOSE

To report on our institutional cohort of patients and review the literature of medulloblastoma patients who developed skull/subdural-based lesions following treatment.

METHODS

Following institutional review board (IRB) approval, we retrospectively reviewed the medical records of four children with a history of treated medulloblastoma who developed non-specific skull-based/subdural lesions incidentally found on surveillance imaging.

RESULTS

Biopsies of the lesions proved the pathology to be low grade and included inflammatory myofibroblastic tumor, cortical fibrous defect consistent with fibroma, fibrous tissue, and fibrous dysplasia. The finding of calvarial or subdural fibrous lesions in children following therapy for medulloblastoma was noted in four out of 201 (136 with available follow-up data) medulloblastoma patients seen or discussed in our institution over the past 10 years.

CONCLUSIONS

These lesions can grow over time and pose a differential diagnostic challenge with metastatic disease when identified. The skull and subdural space should be scrutinized for secondary lesions on surveillance imaging of patients with medulloblastoma who have received craniospinal irradiation as knowledge of this benign occurrence will assist with management.

Calvarial Tuberculosis Presenting with Skin Defect in an Elderly Patient

BACKGROUND

Tuberculosis is a common disease; however, the prevalence of calvarial tuberculosis is very rare. Most cases of calvarial tuberculosis occur in young patients. We report a rare case of calvarial tuberculosis in an elderly patient.

CASE DESCRIPTION

An 89-year-old woman presented with a forehead skin defect. Radiologic imaging showed bony erosion 20 × 10 mm in size with adjacent dural enhancement in the left frontal bone. The patient underwent surgical treatment. Pathology revealed chronic granulomatous inflammation with caseous necrosis, consistent with tuberculosis. Antituberculous medications were prescribed for 6 months.

CONCLUSIONS

A careful assessment should be performed to obtain an appropriate diagnosis in cases of osteolytic lesions of the skull.

Sarcoidosis of the Skull: A Systematic Review

BACKGROUND

Lesions of the skull make up a small but important part of neurosurgical practice. Several systemic disorders may involve the cranial vault including neoplastic and non-neoplastic conditions. Sarcoidosis of the skull is a little-known cause of calvarial involvement that has been rarely reported in the literature. The available information about skull sarcoidosis (SS) is sparse and is not well described; for this reason, we consider that a detailed description of this uncommon condition is necessary.

METHODS

An illustrative case of SS is presented; in addition, a PubMed and Scopus search adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was performed to include studies reporting patients with SS. Different information was analyzed in these cases to describe the characteristics of this condition. Also, different sources of literature were analyzed to complete the description of this clinical entity.

RESULTS

The search yielded 22 cases of patients with SS showing a variety of clinical manifestations. All studies were case reports. Most patients diagnosed with SS had no previous history of systemic sarcoidosis. Different characteristics of SS are analyzed and described in this paper.

CONCLUSIONS

The information collected from this review shows that SS is a rare condition that frequently is observed in patients without previous diagnosis of sarcoidosis. SS may manifest in different ways, and even may be found incidentally in some patients. The diagnosis of SS should be considered when multiple lytic skull lesions are observed, especially in cases of patients without a previous history of malignancy.

Giant skull vault defect in a child caused by Langerhans cell histiocytosis: the "calvaria-eating disease"

Langerhans cell histiocytosis (LCH) is a rare disease of young children that can be difficult to diagnose and treat. Clinical manifestations can sometimes be quite unusual, and bony lesions can reach a large size before treatment is sought. We present a unique case of a 3-year-old male child with a painless giant calvarial defect and cystic swelling. Complete removal of the cyst with curettage of the involved bone margins and cranioplasty was done using bone cement (polymethyl methacrylate, PMMA). However, there was a flare up of the disease due to abnormal inflammatory reaction to PMMA, and cranioplasty bone flap had to be removed. The child did well after PMMA bone flap removal.LCH should be suspected in a male child presenting with a large calvarial defect and no history of trauma. The use of materials, viz., hydroxyapatite, poly-DL-lactide (PDLLA), and PMMA for cranioplasty in LCH, may cause reactivation of the disease process and therefore must be used cautiously in these patients.

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.