Primary extradural meningiomas: a report on nine cases and review of the literature from the era of computerized tomography scanning

Case report of a patient with an intraosseous meningioma presenting as possible metastasis from prostate cancer: Diagnostic dilemma and review of literature

Intraosseous meningiomas are a rare subtype of meningiomas representing approximately 2% of all cases. They can confound a diagnosis of other bone lesions including metastatic tumors. We present a case of a patient with prostate cancer who on staging workup was suspected to have a skull metastasis. Both bone scan and CT Head demonstrated a lesion in the right frontal calvarium. Surgical resection and pathology revealed an intraosseous meningioma. The patient was restaged as having localized prostate cancer and the was offered curative treatment for his malignancy. The case highlights the importance of obtaining tissue diagnosis in cases of radiographic isolated oligometastatic disease in patients with a known primary malignancy.

Primary intraosseous meningioma: a case of early symptomatic calvarial origin meningioma

Primary intraosseous meningiomas are rare extradural tumors. They are typically slow-growing, painless, and asymptomatic until they cause a mass effect. We report a case of a calvarial primary intraosseous meningioma, which became symptomatic despite a very small size. A 67-year-old female with a history of precancerous breast tissue presented with right-sided stroke-like symptoms. Computed tomography showed right parietal convexity irregularity without hemorrhage or infarct. MRI indicated a right parietal calvarial signal abnormality and dural thickening, suggesting metastases or primary osseous neoplasm. A PET scan revealed heterogeneous uptake in the right parietal skull with no other abnormalities. Histology confirmed the diagnosis of primary intraosseous meningioma. Histopathological examination is crucial to avoid misdiagnosis and treatment planning, which may involve wide-margin skull resection, radiation, or both.

Association of imaging classification and histopathological grading in primary intraosseous meningioma of the skull

BACKGROUND

Primary intraosseous meningioma of the skull (PIMS) is a rare type of primary extradural meningioma (PEM) involving cranial bone. The existing literature strongly suggest the importance of radiological feacures in pathological diagnosis of PIMS. Thereby, the aim of this study is to investigate the association between imaging classification and histopathological grading in PIMS.

METHODS

In this retrospective study, we retrospectively analyzed the computed tomography scan/magnetic resonance imaging and pathological data pertaining to patients with pathologically proven PIMS. The association between radiological features, imaging classification, and histopathological grading was analyzed using logistic regression analysis.

RESULTS

In this study, data of 25 patients with PIMS were assessed. The univariate logistic regression analysis results showed significant correlation between histopathological grading and imaging classification (OR: 22.5; 95% CI: 2.552-198.378; p = 0.005), intra- and extracalvarial extension (OR: 7.2; 95% CI: 1.066-48.639; p = 0.043), and tumor margin (OR: 7.19; 95% CI: 1.06-47.61; p = 0.043). According to the results of multivariate logistic regression analysis, imaging classification was the strongest independent risk factor for high-grade PIMS, and the risk of aggressiveness of osteoblastic type of PIMS was 16.664 times higher than that of osteolytic type of PIMS (OR: 16.664; 95% CI: 1.15-241.508; p = 0.039).

CONCLUSIONS

Imaging classification is an independent risk factor for high-grade PIMS.

Case report of a primary ectopic extradural and extraspinal meningioma of the brachial plexus

Primary ectopic extradural and extraspinal meningiomas are rare. We present a unique case of this type of meningioma in the brachial plexus. A 25-year-old man consulted us because of neuropathic supraclavicular pain and the appearance of a supraclavicular mass whose volume had increased. Clinical examination found paresis of the deltoid, biceps brachii and brachialis muscles rated as M4 (MRC) and a strong Tinel sign at the supraclavicular fossa, over the palpable mass. There was no sign pointing towards central nervous system involvement or altered general condition. MRI revealed a mass measuring 53 × 24 mm invading the C5-C6 plexus roots and the primary upper trunk, but not the bone or spinal area. This lesion was hyperintense on DWI/ADC, hyperintense on T2 with hypointense spots, and hypointense on T1 with intense heterogeneous gadolinium enhancement. Excisional biopsy was done 6 months after symptoms started. The tumor had developed at the C5 root, which was fibrous and at the C6 root, which was grossly normal. Anatomical pathology confirmed the WHO grade 1 meningioma, meningothelial and psammomatous histological subtypes. At 6 months, a follow-up MRI found no postoperative tumor remnants or recurrence. During the postoperative course, persistent paralysis of the deltoid muscle at 5 months justified a nerve transfer. This is a rare case of ectopic extraspinal and extradural meningioma of the brachial plexus. The diagnosis of an ectopic meningioma must be considered when a patient presents with a brachial plexus tumor causing neurological deficits. The extradural nature is not sufficient to rule out this diagnosis.

A Case of Recurrence of Benign Convexity Primary Intraosseous Meningioma

Meningiomas originating within the bones of the skull are rare and have been reported as primary intraosseous meningiomas (PIOM). Moreover, PIOMs with a skull base location or malignant pathology are predisposed to recurrence; however, recurrence is quite rare among PIOMs characterized by a convexity location and benign pathology. Here, we present a case of extensive recurrence of a convex intraosseous meningioma with benign pathology. A 72-year-old woman presented with a headache to our hospital. Gd contrast-enhanced magnetic resonance imaging revealed an enhanced tumor in the left frontal to the parietal region extending through the calvarial bone and invading the subdural space and subcutaneous tissue. Skull radiograph and computed tomography identified a remarkable osteolytic change in the lesion. Macroscopic complete resection (MCR) of the tumor and the surrounding tissues was performed. The tumor was histopathologically diagnosed as a transitional meningioma (World Health Organization grade 1). Seven years after the surgery, the patient presented with dysarthria, and the recurrence of the tumor was identified as massive lesions extending through the calvarial bone to the orbital bone, partially protruding into the brain and scalp. MCR was performed again, with the reconstruction of the skull for an extensive calvarial area using a titanium plate. This case is unique due to the extensiveness of the recurrent tumor and its rarity. Here, we report the details of the clinical course and discuss the characteristics of this case.

Complete loss of E-cadherin expression in a rare case of metastatic malignant meningioma: a case report

BACKGROUND

Hematogenous tumor spread of malignant meningiomas occurs very rarely but is associated with very poor prognosis.

CASE PRESENTATION

We report an unusual case of a patient with a malignant meningioma who developed multiple metastases in bones, lungs and liver after initial complete resection of the primary tumor. After partial hepatic resection, specimens were histologically analyzed, and a complete loss of E-cadherin adhesion molecules was found. No oncogenic target mutations were found. The patient received a combination of conventional radiotherapy and peptide receptor radionuclide therapy (PRRT). Due to aggressive tumor behavior and rapid spread of metastases, the patient deceased after initiation of treatment.

CONCLUSIONS

E-cadherin downregulation is associated with a higher probability of tumor invasion and distant metastasis formation in malignant meningioma. Up to now, the efficacy of systemic therapy, including PRRT, is very limited in malignant meningioma patients.

A Primary Intraosseous Meningioma: A Rare Case of Malignancy with High Proliferative Ability

Primary intraosseous meningioma (PIM) is a rare tumor that arises in the skull. Histopathologically, it is generally described as a slow-growing, benign lesion. However, on rare occasions, PIM presents as a malignancy with high proliferative ability, which requires maximal resection, adjuvant radiotherapy, and subsequent careful follow-up. Because of the rarity of such cases, they present a diagnostic challenge with unusual pathological findings. Herein, we report a case of a primary intraosseous anaplastic meningioma with extensive invasion inside and outside the skull, along with the results of whole-genome analysis. Histopathological diagnosis was a World Health Organization grade 3 anaplastic meningioma. In the literature, only two cases of anaplastic PIM have been reported, so its characteristics and treatment are poorly understood. Our patient was successfully treated with tumor resection, followed by intensity-modulated radiation therapy. Follow-up imaging studies revealed no recurrence or distant metastasis, including to lung, liver, and bone, at 8 months after the surgery.

Primary ectopic meningioma in the thoracic cavity: A rare case report and review of the literature

Background

Meningioma is a common type of intracranial tumor in adults. It rarely arises in the chest, with only a few case reports in the English literature. Here, we report the case of a patient with a primary ectopic meningioma (PEM) located in the thoracic cavity.

Case presentation

A 55-year-old woman presented with exercise-induced asthma, chest tightness, intermittent dry cough and fatigue for several months. Computed tomography revealed the presence of a huge mass in the thoracic cavity, with no connection to the spinal canal. Lung cancer and mesothelioma were suspected, and surgery was performed. Grossly, the mass was a grayish-white solid 9.5 cm × 8.4 cm × 5.3 cm in size. The microscopic morphology of the lesion was consistent with that of typical central nervous system meningioma. The pathological subtype was transitional meningioma. The tumor cells were arranged in a fascicular, whorled, storiform and meningithelial pattern, with occasional intranuclear pseudo-inclusions and psammoma bodies. In focal areas tumor cells were considerably dense, and the cells were round or irregular in shape, with less cytoplasm, uniform nuclear chromatin, and visible nucleoli and mitoses (2/10 HPF). By immunohistochemistry, the neoplastic cells showed strong and diffuse staining with vimentin, epithelial membrane antigen and SSTR2 with variable expression of PR, ALK and S100 protein. However, the cells were negative for GFAP, SOX-10, inhibin, CD34, STAT6, smooth muscle actin, desmin, CKpan, D2-40, WT-1, CK5/6 and CD45. The highest proliferation index by Ki-67 was 15%. The abnormal expression of ALK led to the initial misdiagnosis of an inflammatory myofibroblastic tumor. After 12 months of follow-up, no disease progression was observed.

Conclusion

The presence of primary ectopic meningiomas in the thoracic cavity is extremely rare, and this tumor is easily misdiagnosed clinically. Imaging is suggested to determine the location and possible differential diagnosis, while the final diagnosis should be via pathological examination. Immunohistochemistry is crucial for disease diagnosis. Owing to our limited knowledge of PEM, its pathogenesis and tissue of origin remain unclear. Clinicians should pay close attention to such potential patients. The present case report may provide insights into the diagnosis and therapy of patients with this tumor.

Asymptomatic Intraosseous Meningioma of the Humerus: A Case Report and Review of the Literature

Meningiomas are the most common central nervous system tumor. They are typically benign neoplasms but may produce neurological symptoms due to mass effect. Meningiomas may also extend to extradural locations; however, these account for only a small percentage of all meningiomas. Most extradural meningiomas arise in intraosseous locations, usually within the cranial bones or vertebrae. However, this is a rare case of extradural extension of an asymptomatic intracranial meningioma to the proximal humerus in the absence of any musculoskeletal symptoms. To the best of our knowledge, this presentation of an extradural intraosseous meningioma has not previously been reported in the literature. We present a case of an incidental intraosseous meningioma in a 66-year-old man. This patient was initially being screened for metastasis of stage IA1 adenocarcinoma of the lung, and a positron emission tomography (PET) scan revealed a focus of activity in the proximal diaphysis of the right humerus suspicious for malignancy. The upper extremity magnetic resonance imaging (MRI) demonstrated an indeterminate lesion. Curettage of the humeral lesion revealed an intraosseous psammomatous meningioma without evidence of metastatic lung carcinoma. Our case report aims to illustrate the importance of considering alternative metastatic sources, such as intracranial meningioma, during the investigation of an indeterminate bony lesion. This is the first case to illustrate asymptomatic intraosseous meningioma in an appendicular skeletal location, highlighting the need for thorough source investigation.

Primary intraosseous meningioma with subcutaneous and dural invasion: A case report and literature review

Primary intraosseous meningiomas (PIOMs) are a rare subset of meningiomas, comprising fewer than 1% of all such tumors. Furthermore, PIOMs presenting as osteogenic lesions that invade both the dura and subcutaneous tissue are extremely rare. Unlike intracranial meningiomas, diagnosing and treating PIOMs are challenges due to their insidious clinical behavior and a lack of clear radiological diagnostic criteria. We report the case of a 60-year-old female with headache and a slightly outward protrusion of the parietal region of the skull. CT showed an osteogenic lesion in the right parietal bone. MR imaging indicated mild to moderate homogeneous enhancement with an intense dural reaction. The suggested clinical diagnosis was lymphoma, so we performed a skull biopsy, which revealed an intraosseous benign meningioma. A precise resection strategy was planned with a neuronavigation system accompanied by a one-step customized titanium mesh cranioplasty. The lesion was completely removed, and pathological analysis confirmed a meningothelial meningioma (WHO Grade I) of intraosseous layer origin invading the dura mater and subcutaneous tissue. This case highlights the need for an initial biopsy when the lesion is difficult to diagnose on imaging. Complete resection should be attempted to minimize the risk of recurrence.

Intraosseous meningioma, a rare presentation of a common brain tumor: illustrative case

BACKGROUND

The subset of extradural meningiomas arising from bone is called primary intraosseous meningioma. The present article outlines the clinical presentation, investigation, surgical management, and clinical outcomes of a challenging case of intraosseous meningioma.

OBSERVATIONS

A 27-year-old male presented with new-onset seizure of 3 years' duration and growing painless hard swelling involving the left frontoparietal bone, the medial aspect of the left orbit, the nasal bone, and the temporal bone. Brain computed tomography showed a diffuse intradiploic space osseous lesion with a ground-glass appearance. The patient underwent bifrontal craniotomy and tumor excision. The histopathological sections showed the presence of classic whorls of meningothelial cells around reactive bony tissue suggestive of intraosseous meningioma. Postoperatively, the patient was neurologically intact, and he was discharged in a stable condition. The outcome of this case was satisfactory.

LESSONS

The treatment of primary intraosseous meningioma is wide surgical excision together with the involved dura and any intradural tumor. The location of the tumor determines the approach and the amount of resection, keeping in mind preservation of function. The use of adjuvant therapy is reserved for cases of tumor recurrence or an atypical type.

The use of an endoscopic endonasal approach for a secondary intraorbital meningioma: illustrative case

BACKGROUND

Meningiomas are the most frequent primary tumors in the central nervous system (CNS), but intraorbital location is uncommon and accounts for only 0.2% to 4% of all CNS meningiomas. Lesions in this compartment could be classified as primary, secondary, or ectopic. The close relationship with the optic nerve sheath is a landmark to identify the tumor as primary, whereas secondary tumors commonly come from an extension of an intracranial meningioma, and ectopic meningioma is a concept not yet completely established.

OBSERVATIONS

The authors present a rare case of a secondary intraorbital meningioma operated through an endoscopic endonasal approach. Secondary meningiomas at the medial orbit are very uncommon, given their more common superior and lateral location as an extension of sphenoid meningiomas. The endoscopic endonasal route provides direct access to the medial orbit. The authors present an illustrative case of a meningioma located at the medial orbit and resected through an endoscopic endonasal approach that provided excellent visualization and anatomical exposure. Additionally, the authors review the concept and possible similarities between secondary and ectopic intraorbital meningiomas.

LESSONS

An endoscopic endonasal approach should be considered as a feasible treatment option for intraorbital meningiomas, especially if they are in the medial orbital wall.

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.

Primary Extradural Ectopic Orbital Meningioma in a Child

The authors describe a rare case of primary extradural ectopic meningioma of the orbit in a 13-year-old female managed with surgical excision, adding to the very limited literature of this diagnosis in children. This is the second case to show a radiological abnormality in the gyrus rectus and olfactory bulb; however, in our case, there was no radiological evidence of connection seen.

Surgical Challenges of Meningiomas with Extracranial Invasion: A Clinical Study

Objective: Meningiomas are mostly benign tumors located intracranially and intradurally, but they can rarely show extradural and extracranial growth. Surgical treatment of extracranial meningiomas is specifically challenging. In this study, we present an illustrated surgical series to convey our experience in treating meningiomas with extracranial extension. Methods: We retrospectively reviewed 11 patients with meningioma who underwent surgery between 2008 and 2020. In these patients, both intracranial and extracranial components were confirmed both radiologically and intraoperatively. Results: The patients were 7 males and 4 females with a mean age of 55.4 years. Most presented with facial disfigurement or asymmetrical growth of their skull. The most common symptom at presentation was headache. The most common location of meningiomas was the frontal region and that of extracranial growth was the paranasal sinuses and parietal bone invasion. We recognized two distinct modalities of bone destruction: hyperostosis (n=3) and osteolysis (n=8). Pathological study revealed atypical features in 6 patients. Preop embolization was attempted in 4 patients and proved difficult. Proper embolization was achieved only in one patient. The most commonly encountered surgical challenges were large calvarial and cranial base defects due to bone erosion, dural defects, and managing the superior sagittal sinus with parietal tumors. Excessive blood was of a particular concern and was managed by simple scalp clips, intraoperative transfusion, and conservative approach for tumor extensions into paranasal sinuses. No perioperative mortality occurred. Postoperative CSF fistulas beneath the scalp were common complications but conservatively managed with pressure wrapping. No cranial base CSF fistula developed. Calvarial reconstruction was performed with PMMA cement where needed. Conclusions: Meningiomas with extracranial extension are surgically challenging but treatable tumors. It contains fine neurosurgical trics in its treatment and follow-up.

Bone Invasive Meningioma: Recent Advances and Therapeutic Perspectives

Meningioma is the most common primary neoplasm of the central nervous system (CNS). Generally, these tumors are benign and have a good prognosis. However, treatment can be challenging in cases with aggressive variants and poor prognoses. Among various prognostic factors that have been clinically investigated, bone invasion remains controversial owing to a limited number of assessments. Recent study reported that bone invasion was not associated with WHO grades, progression, or recurrence. Whereas, patients with longer-recurrence tended to have a higher incidence of bone invasion. Furthermore, bone invasion may be a primary preoperative predictor of the extent of surgical resection. Increasing such evidence highlights the potential of translational studies to understand bone invasion as a prognostic factor of meningiomas. Therefore, this mini-review summarizes recent advances in pathophysiology and diagnostic modalities and discusses future research directions and therapeutic strategies for meningiomas with bone invasion.

Primary Intraosseous Osteolytic Meningioma with Aggressive Clinical Behaviour: Clinico-Pathologic Correlation and Proposed New Clinical Classification

(1) Introduction: Primary intraosseous osteolytic meningiomas (PIOM) are non-dural-based tumors predominantly presenting an osteolytic component with or without hyperostotic reactions. They are a subset of primary extradural meningiomas (PEM). In this study, we present a peculiar case with a systematic literature review and propose a new classification considering the limitations of previous classification systems. (2) Materials and Methods: Using a systematic search protocol in Google Scholar, PubMed, and Scopus databases, we extracted all case studies on PIOM published from inception to December 2020. A 46-year-old female patient form Dhaka, Bangladesh, was also described. The search protocol was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. (3) Results: Here, we present a 46-year-old female patient with PIOM who successfully underwent bifrontal craniotomy and gross total removal (GTR) of the tumor. At 6-month follow-up, no tumor recurrence was shown. Including our new case, 55 total cases from 47 articles were included in the analysis. PIOMs were in closer frequency among males (56.4%) and females (43.6%). The most common tumor location was the frontal and parietal calvarium, most commonly in the frontal bone (29.1%). Surgical resection was the predominant modality of treatment (87.3%); only 1.8% of patients were treated with radiotherapy, and 5.4% received a combination of surgery and radiotherapy. Gross total resection (GTR) was achieved in 80% of cases. Extracranial extension was reported in 41.8% of cases, dural invasion in 47.3%, and recurrence in 7.3%. Whole-body 68 Ga-DOTATOC PET/CT has also been reported as a useful tool both for differential diagnosis, radiotherapy contouring, and follow-up. Current treatments such as hydroxyurea and bevacizumab have variable success rates. We have also suggested a new classification which would provide a simple common ground for further research in this field. (4) Conclusions: Surgical resection, especially GTR, is the treatment of choice for PIOM, with a high GTR rate and low risk of complications and mortality. More research is needed on the differential diagnosis and specific treatment of PIOM.

Posttraumatic rapid growing extradural meningioma: A case report on the effectiveness of echosonography

Background:

Most meningiomas related to head trauma have been reported to show intradural lesions; however, they can also occur as primary extradural meningiomas (PEMs) and have often been reported to histologically demonstrate atypical or malignant subtypes. Therefore, early detection and complete resection of related tissues are required; however, to date, only a few PEM cases related to trauma or injury have been reported. Herein, we present a patient with a rapidly growing posttraumatic PEM, in which echosonography is efficient not only for early diagnosis but also for intraoperative strategies.

Case Description:

A 62-year-old male presented to a nearby clinic with a complaint of a painless head bump that gradually grew larger in relation to trauma 6 weeks earlier. He underwent echosonography and pointed out the possibility of a cranial tumor and consulted our hospital. Although preoperative imaging studies, such as computed tomography or magnetic resonance imaging, did not provide reliable information on dura mater invasion, echosonography demonstrated dural invasion and intradural lesions in which large vessels passed the surface of the lesion. Based on these findings, we could safely resect the lesion within a sufficient range.

Conclusion:

Echosonography may not only be a cue for an early diagnosis but also provide important information for the treatment strategy of PEM that is related to head trauma.

Atypical intradiploic meningioma: A case report and review of the literature

Background:

Intradiploic meningiomas with osteolytic bony changes are rarely reported in the literature. Intradiploic meningiomas are usually slow-growing benign lesions but atypical histopathology predicts aggressive behavior. Atypical intradiploic meningiomas (WHO Grade II) have some controversies in the management which are highlighted in this article.

Case Description:

A 40-year-old male, with a history of trauma to the head 12 years back, presented with a hard, slow-growing painless swelling exactly at the site of trauma. On imaging, lesion was intradiploic one with osteolytic margins and homogeneously enhancing on contrast magnetic resonance imaging. Biopsy was that of atypical meningioma (WHO Grade II).

Conclusion:

Atypical meningiomas with osteolytic changes are rarely reported in the literature. Because of potential aggressive behavior, they need a regular follow-up with radiological imaging.

Type III Cutaneous Atypical Meningioma of the Scalp

Cutaneous meningiomas can be a diagnostic challenge, as they are not only found very rarely in extracranial sites, including the skin, but also because of the histopathologic overlap with several other spindle cell tumors. Cutaneous meningiomas are divided into type I (congenital), type II (ectopic) and type III (via a direct extension) lesions. We present a rare case of atypical meningioma of the skin in a 71-year-old female. A patient presented with a painful and enlarging lesion on the left central frontal scalp. Biopsy showed bone and soft tissue with involvement of a spindle cell neoplasm, consisting of whorled nests with atypical features, including variably increased mitotic index, areas of hypercellularity, and sheeted architecture. The overall findings were consistent with an atypical meningioma (WHO grade 2). Atypical meningiomas constitute only 5 - 15% of all meningiomas. A skull MRI was later performed, which demonstrated a left frontal tumor consistent with an atypical meningioma that had eroded through the skull. Dermatopathologists should consider cutaneous meningioma as a differential diagnosis of spindle cell neoplasms of the skin and subcutaneous tissue in head and neck. This article is protected by copyright. All rights reserved.

Isolated Intraconal Meningioma

Purpose

To report a rare case of isolated intraconal meningioma.

Case Report

A 24-year-old woman presented with painless proptosis in her left eye which started and progressed during her pregnancy about 10 months ago. Hertel exophthalomometry revealed anterior displacement of the globe with 4 mm of proptosis which was remarkable. Magnetic resonance imaging (MRI) demonstrated an intraconal circumscribed oval-shaped mass with hypointense signals on T1-weighted images and hyperintense signals on T2-weighted images, mimicking cavernous hemangioma. This mass, however, was free of any connections to optic nerve or bones. Due to the imaging characteristics, more prevalent diagnoses like cavernous hemangioma were placed on the top of the differential diagnoses list. However, during the surgical excision, the tumor’s consistency and gross features were not compatible with cavernous hemangioma. The pathologic findings instead determined meningotheliomatous meningioma, a very rare condition, which was far from our expectations prior to the surgery.

Conclusion

Ectopic orbital meningiomas are rare tumors that are not easily diagnosed without postoperative histopathology. Despite its low prevalence, they should be considered in the differential diagnosis list of intraconal masses with hypointense signals on T1-weighted images and hyperintense signals on T2-weighted images.

Intraosseous meningioma mimicking osteosarcoma

Background

Predominantly intraosseous meningiomas are rare entities that include true primary intraosseous meningiomas (PIM), as well as meningiomas that may show extensive bone involvement, such as en plaque meningiomas. Different hypotheses have been proposed to decipher the origin of PIMs, such as ectopic arachnoid cap cell entrapment during birth or after trauma. Surgical resection is the treatment of choice of such lesions.

Case presentation

We present a case of a 65-year-old man with an enlarging mass in the parieto-occipital region that grew slowly and progressively over 13 years, following head trauma during a motor vehicle accident. One year prior to presentation, he started experiencing daily holocranial headaches and blurry vision. CT and MRI studies revealed a permeative midline calvarial lesion measuring 14 cm in greatest dimension with extensive periosteal reaction, extension into the subcutaneous soft tissues, subjacent dural thickening and intracranial extension with invasion of the superior sagittal sinus. The favored pre-operative clinical diagnosis was osteosarcoma. The abnormal calvarium was excised and histopathological examination confirmed the diagnosis of a predominantly intraosseous calvarial meningioma, WHO grade I.

Conclusions

The present case highlights the importance of histopathologic diagnosis in guiding therapeutic decisions and reiterates the necessity of considering PIM or meningiomas with extensive intraosseous component in the differential diagnosis of calvarial masses, even when imaging suggests a neoplasm with aggressive behavior, such as osteosarcoma.

Adjuvant radiotherapy in a case of atypical meningioma after gross total resection: an unresolved issue

We present a case of a 48-year-old man diagnosed with parasagittal atypical meningioma (AM) involving biparietal bones with intracranial and extracranial extension up to galea aponeurotica of the scalp. The patient underwent Simpson's grade 2 resection (GTR (gross total tumour resection) with coagulation of dural attachment). Currently, in AMs, the role of adjuvant radiotherapy is controversial after GTR. Here, through this case, we have discussed in detail issues related to tumour origin, that is, primary versus secondary extradural meningioma and controversial topics regarding the role of adjuvant radiotherapy in the management of AMs. We have presented our radiation treatment strategy addressing the high-risk zones related to tumour extension in this case.

Fronto-orbito-ethmoidal intradiploic meningiomas: A case study with systematic review

Background

Primary intradiploic meningiomas, extra-axial tumors arising primarily in the skull, are rare. The authors reported a complex case of intradiploic intraosseous metaplastic meningioma of the left medial wall and orbital roof with the left frontal sinus invasion and left ethmoidal body bone substitution. The authors also conducted a systematic review concerning diagnosis and management of patients affected by purely calvarial intradiploic meningiomas along with a focus on fronto-orbito-ethmoidal ones.

Methods

A literature search was conducted using PubMed and Scopus databases according to preferred reporting items for systematic reviews and meta-analysis statement and with the following Mesh terms: Intradiploic, intraosseous, calvarial, and meningioma. Eligibility criteria were limited by the nature of existing literature on intradiploic meningiomas, consisting of only case series, and case reports.

Results

A total of 128 published studies were identified through our search. 41 studies were included in this systematic review, 59 patients with a female/male ratio of 1.2/1. The mean age of the patients is of 47.69 years (range 3-84 years). Only seven out of 59 patients (11.9%) presented a complex intradiploic meningioma located in fronto-orbito-ethmoidal region like our case. In almost all patients, a gross-total resection was performed (96.6%) and only in two patients (3.4%) a subtotal resection was achieved.

Conclusion

The authors shared this successfully treated case to add to the overall clinical experience in the management of this rare subtype tumor, with the hope that more studies are conducted to further address the mechanism of intradiploic meningiomas development.

Giant Intraosseous Meningioma Associated with Calvarial Hyperostosis and Subcutaneous Invasion: Case Reports and Literature Review

Most meningiomas grow intracranially, and primary intraosseous meningioma is rarely reported. We present two rare surgical cases of giant intraosseous meningothelial meningioma. The first patient was a 35-year-old male with parietal skull deformity without neurological symptoms. Total resection was successful. The origin was the parasagittal intraosseous layer, and the superior sagittal sinus was partially opened. The second patient was a 20-year-old female with a slightly upward protrusion of the frontal skull without pain or neurological deficits. The lesion was totally resected, and the origin was the parasagittal intraosseous layer invading into the dura matter and subcutaneous layer. The clinical management of these cases presented a surgical challenge because of detachment and repair from venous sinuses. The current report provides surgical tips for such rare diseases and is a good reference for the future treatment of similar diseases.

Primary intraosseous meningioma of the vertebra: illustrative case

BACKGROUND

Primary intraosseous meningiomas (PIMs) are rare, and PIMs of the vertebrae have not yet been reported. The authors report a case of primary meningioma arising from the vertebrae.

OBSERVATIONS

A 49-year-old man presented with lower back pain and numbness in both lower extremities. Lumbar spine magnetic resonance imaging revealed an L2 pathological fracture with epidural and paraspinal invasion. The patient had undergone a first palliative decompression and fixation surgery, and the diagnosis turned out to be a World Health Organization grade III anaplastic meningioma based on histopathology. The tumor had progressed after first operation and radiation therapy, and the patient was referred to the authors’ institute for excision. The patient had an uneventful postoperative course after a revisional total en bloc spondylectomy of L2.

LESSONS

The authors present a rare case of PIM of the vertebrae with epidural and paraspinal invasion. Careful preoperative assessment and surgical planning is crucial for successful patient management.

Primary extradural tumors of the spinal column: A comprehensive treatment guide for the spine surgeon based on the 5th Edition of the World Health Organization bone and soft-tissue tumor classification

BACKGROUND

In 2020, the World Health Organization (WHO) published the 5th version of the soft tissue and bone tumor classification. Based on this novel classification system, we reviewed the current knowledge on all tumor entities with spinal manifestations, their biologic behavior, and most importantly the appropriate treatment options as well as surgical approaches.

METHODS

All tumor entities were extracted from the WHO Soft-Tissue and Bone Tumor Classification (5th Edition). PubMed and Google Scholar were searched for the published cases of spinal tumor manifestations for each entity, and the following characteristics were extracted: Growth pattern, ability to metastasize, peak age, incidence, treatment, type of surgical resection indicated, recurrence rate, risk factors, 5-year survival rate, key molecular or genetic alterations, and possible associated tumor syndromes. Surgical treatment strategies as well as nonsurgical treatment recommendations are presented based on the biologic behavior of each lesion.

RESULTS

Out of 163 primary tumor entities of bone and soft tissue, 92 lesions have been reported along the spinal axis. Of these 92 entities, 54 have the potential to metastasize. The peak age ranges from conatal lesions to 72 years. For each tumor entity, we present recommended surgical treatment strategies based on the ability to locally destruct tissue, to grow, recur after resection, undergo malignant transformation as well as survival rates. In addition, potential systemic treatment recommendations for each tumor entity are outlined.

CONCLUSION

Based on the 5th Edition of the WHO bone and soft tumor classification, we identified 92 out of 163 tumor entities, which potentially can have spinal manifestations. Exact preoperative tissue diagnosis and interdisciplinary case discussions are crucial. Surgical resection is indicated in a significant subset of patients and has to be tailored to the specific biologic behavior of the targeted tumor entity based on the considerations outlined in detail in this article.

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.

Virtual Surgical Planning for Intracranial Intraosseous Meningioma Reconstruction

OBJECTIVE

To assess the use of custom-made intracranial implants and three-dimensional cutting guides to direct the intracranial, intraorbital, and temporal reconstruction process for intraosseous meningioma.

METHODS

A retrospective analysis was conducted on 6 patients who were operated on by the senior author for intraosseous meningioma between 2017 and 2020. Three-dimensional models of the maxillofacial skeleton were created from preoperative virtual planned reconstruction and postoperative computed tomography scan images in the Mimics and 3-Matics software. Orbital reconstruction and temporal implant accuracy assessments were performed through the Materialise Mimics software.

RESULTS

Orbital cone volume had a mean discrepancy between the planned and actual orbital volume of 1.5% ± 1.6%. The reconstructed postoperative orbital volume was within 1.3% ± 2.0% of the unaffected orbit. Temporal bone reconstructions had a mean implant accuracy of 81.0%.

CONCLUSIONS

Our results show that the postextirpative intracranial applications of virtual surgical planning are particularly suited for high fidelity reconstructions such as orbital reconstructions, as well as temporal reconstructions with intraoperative adjustments. Custom implants and virtual three-dimensional planning is particularly ideal and promising for intraosseous meningiomas given the involvement of complex intracranial and intraorbital bony structures.

Hyperostosing sphenoid wing meningiomas

Some sphenoid wing meningiomas are associated with a significant hyperostotic reaction of the adjacent sphenoid ridge that may even exceed the size of the intradural mass. The decision-making process and surgical planning based on neuroanatomic knowledge are the mainstays of management of this group of lesions. Given their natural history and biologic behavior, many hyperostosing meningiomas at this location require long-term management analogous to a chronic disease. This is particularly true when making initial decisions regarding treatment and planning surgical intervention, when it is important to take into consideration the possibility of further future interventions during the patient's life span.

Microsurgical Resection of a Primary Intraosseous Meningioma Encasing the Superior Sagittal Sinus

Primary intraosseous meningiomas (PIMs) are an infrequent variant of meningiomas characterized by hyperostosis and brain compression. En bloc surgical resection of giant PIMs involving critical structures such as venous sinuses or cranial nerves could be associated with significant morbidity. The objective of this report is to demonstrate the safety and feasibility of piecemeal resection of PIMs involving the superior sagittal sinus and frontal sinus. A 54-year-old female with a large 5 cm thick bifrontal primary intra-osseous meningioma encasing the anterior segment of the superior sagittal sinus and frontal sinus underwent a bifrontal craniotomy with piecemeal microsurgical resection of the lesion, complete frontal sinus exoneration, and a synthetic cranioplasty. Clinical outcome was measured by extent of resection, preservation of cortical draining veins and postoperative course. A Simpson grade I resection of the lesion was achieved following piecemeal resection of the giant PIM without clinical or radiographic evidence of venous infarct or injury. The postoperative course was uncomplicated, and the patient was discharged home 3 days after cranioplasty. A complete resection of a giant bifrontal PIM with superior sagittal sinus encasement and frontal sinus involvement can be achieved safely via a piecemeal approach without significant intra-operative morbidity.

68Ga-DOTATOC-PET/CT-guided resection of a primary intraosseous meningioma: technical note

Primary intraosseous meningiomas (PIMs) are rare tumors that present with a variable radiological appearance and a clinical behavior that is considerably different from that of intracranial meningiomas. Treatment of PIMs consists of complete resection, which may be difficult to achieve due to the lack of clear tumor margins on conventional imaging studies. PET/CT using 68Ga-DOTA-conjugated peptides has been used for the diagnosis and treatment planning of different types of meningiomas due to these tracers' affinity to somatostatin receptors, which are found in most meningiomas. However, this imaging modality's use as an intraoperative adjunct has not been reported for PIMs. In this technical note, the authors describe a [68Ga-DOTA0-Tyr3]octreotide (68Ga-DOTATOC)-PET/CT-guided resection of a PIM. In this case, the area of increased uptake in the 68Ga-DOTATOC-PET/CT study extended well beyond the tumor margins identified on MRI. The patient's pathology report confirmed the presence of tumor cells within peripheral bone, which macroscopically appeared normal. The authors propose 68Ga-DOTATOC-PET/CT as a valuable adjunct in the surgical management of PIMs and offer a reasonable justification for its use based on current evidence. Its use for intraoperative image guidance may aid neurosurgeons in achieving a complete resection, thus minimizing the risk of recurrence of this complex pathological entity.

Benign purely intraosseous meningioma of the skull: Diagnosis and surgical outcomes

Primary intraosseous meningioma (PIM) is a rare subtype of extradural meningiomas that originates within bone. We aimed to characterize the clinical, radiographic, and pathologic features of PIM and the resulting outcomes following resection. Herein we examined a retrospective case series of all patients with a pathologically confirmed WHO grade I PIM that were managed at one of three tertiary care centers. Patients with tumors that demonstrated extraosseous extension or involvement of the dura mater were excluded. The main outcomes included surgical safety and duration of local tumor control. Nine patients were identified with benign PIMs, presenting with headaches or painless enlarging subcutaneous masses if involving the calvarium or with neurologic deficits if involving the skull base, or otherwise incidentally identified. Surgery was pursued for symptomatic relief and/or tissue diagnosis. Lesions were evaluated by radiographic imaging - including sensitive detection by plain X-ray films - and definitive diagnosis ascertained by histopathological examination. Maximal resection of both calvarial and skull base lesions was safely tolerated. PIM represents a rare benign skull lesion, whose identification depends on the integration of radiographic findings with intraoperative findings and histopathological confirmation; it should be considered in the differential for slow-growing expansile intraosseous lesions of the skull.

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.

Primary intraosseous meningioma of the calvarium: A systematic review

BACKGROUND

Primary intraosseous meningiomas (PIM) of calvarial origin are a small subset of meningiomas that arise from and occur within the calvarial bone. Its definition is often confused with other forms of non-dural based intracranial meningiomas, which has made previously published retrospective reviews heterogenous, non-specific and sometimes inaccurate. We present a systematic review of calvarial PIM.

METHODS

Using a systematic search protocol that included databases such as PubMed, Web of Science and Embase, we extracted all human studies on PIM published from inception to December 2017. This systematic review includes case reports and retrospective reviews that specifically described PIM.

RESULTS

On review of 166 articles identified with the systematic search protocol, 69 articles were analyzed. These comprised of 64 case reports, 1 case series and 4 retrospective reviews. 111 patients with PIM of calvarial origin were analyzed, 58 % of which were females and 42 % males. The mean patient age was 51 years and the frontal bone was the most common tumor location, occurring in 26.1 % of the cases. Surgical resection was the predominant modality of treatment in 97.2 % of the cases, and gross total resection was achieved in 84 % of cases that reported extent of resection. There were no recurrences for grade I meningiomas. However, all grade III meningiomas recurred and 33.3 % of grade II meningiomas showed recurrence with a mean postoperative follow-up interval of 20 months. Statistical analysis using Fisher's exact test showed the recurrence rate to be strongly associated with WHO tumor grade (p-value <0.001).

CONCLUSION

There is statistically significant increased recurrence rate for calvarial PIM of higher grades, and we recommend close follow-up in those cases. Surgical resection remains the overwhelming treatment of choice for calvarial PIM, and it has a high gross total resection rate and low risk of complications and mortality.

Imaging and diagnostic advances for intracranial meningiomas

The archetypal imaging characteristics of meningiomas are among the most stereotypic of all central nervous system (CNS) tumors. In the era of plain film and ventriculography, imaging was only performed if a mass was suspected, and their results were more suggestive than definitive. Following more than a century of technological development, we can now rely on imaging to non-invasively diagnose meningioma with great confidence and precisely delineate the locations of these tumors relative to their surrounding structures to inform treatment planning. Asymptomatic meningiomas may be identified and their growth monitored over time; moreover, imaging routinely serves as an essential tool to survey tumor burden at various stages during the course of treatment, thereby providing guidance on their effectiveness or the need for further intervention. Modern radiological techniques are expanding the power of imaging from tumor detection and monitoring to include extraction of biologic information from advanced analysis of radiological parameters. These contemporary approaches have led to promising attempts to predict tumor grade and, in turn, contribute prognostic data. In this supplement article, we review important current and future aspects of imaging in the diagnosis and management of meningioma, including conventional and advanced imaging techniques using CT, MRI, and nuclear medicine.

Primary intraosseous meningioma: clinical, histological, and differential diagnostic aspects

OBJECTIVE

Primary intraosseous meningioma (PIM) is a rare manifestation of meningioma, a benign, neoplastic lesion of the meninges. Its characteristic appearance is hyperostosis, while no or only minimal dural changes can be observed. This study aims to characterize this rare entity from both a clinical and histopathological point of view in order to improve clinical management.

METHODS

In the years 2009-2017, 26 cases of PIM were diagnosed using MRI and CT scans. In 16 cases the indication for resection was given, and specimens were further examined using a multilevel approach, including histological and immunohistochemical analyses. Additionally, the local database was searched for all cases of meningiomas, as well as osteosclerotic differential diagnoses-i.e., fibrous dysplasia, Paget's disease of bone, and other benign osteosclerotic lesions.

RESULTS

In this study, PIM represented 2.4% of all meningiomas with a predominant occurrence in females (85%). Regarding the initial manifestation, PIMs show a slightly earlier onset than meningiomas. While most PIMs are located in the sphenoid bone, associated calcifications were visible in 58% of the cases on CT scans. Most of the cases were classified as WHO grade I (93%) and meningotheliomatous meningiomas (91%). Tumor growth was associated with an increased bone resorption followed by massive osteoid deposition and consecutive sclerosis. The frequently observed frayed appearance results from multiple bony canals, which contain blood vessels for the blood supply of the highly vascularized tumor tissue.

CONCLUSIONS

PIM is a rare but important differential diagnosis for osteosclerotic lesions of the skull, especially in women. Tumor-induced, cellular-mediated bone resorption and formation may play a central role in the underlying pathogenesis.

Intraoperative frozen cytology of intraosseous cystic meningioma in the sphenoid bone

Meningiomas in bone are rarely subjected to fine-needle aspiration diagnosis, and those arising in the skull bone with a cystic presentation are rare. A 24-year-old woman presented with subdural hemorrhage, and subsequent radiology depicted an osteolytic mass-like lesion in the sphenoid bone. Intraoperatively, a solid and cystic hemorrhagic lesion mimicking an aneurysmal bone cyst was observed in the sphenoid bone with dural tearing. Frozen cytology showed singly scattered or epithelioid clusters of round to elongated cells intermixed with many neutrophils. Tumor cells had bland-looking round nuclei with rare prominent nucleoli and nuclear inclusions and eosinophilic granular to globoid cytoplasm in capillary-rich fragments. Histology revealed intraosseous meningothelial and microcystic meningioma (World Health Organization grade 1) in right lesser wing of the sphenoid bone. Considering its unusual location and cytologic findings, differential diagnoses included chordoma, chondroma, chondrosarcoma, and aneurysmal bone cyst. The present case posed a diagnostic challenge due to possible confusion with these entities.

Computed tomographic imaging of meningiomas

Although magnetic resonance imaging (MRI) has surpassed computerized tomography (CT) as the imaging modality of choice, there are certain instances when CT should be a preoperative requisite for meningioma surgical resection. Given its superior bone definition and the propensity for meningiomas to invade bone (as evidenced by hyperostosis on imaging), CT can be extremely helpful to the surgeon when planning and evaluating postoperatively the extent of bone removal during tumor resection. Advances in CT imaging also allow for visualization of the adjacent arterial and venous vasculature to determine feasibility of resection and likelihood of adjuvant treatments such as radiosurgery to a tumor residuum. For skull base tumors high-resolution CT imaging as part of the standard neuronavigation sequences can help evaluate bony anatomy and planning of surgical approaches, in particular for cranial base tumors. Finally, 3D-CT imaging is important in the design of cranial prostheses, which may be required to repair defects as a result of resection.

Proptosis, Orbital Pain, and Long-Standing Monocular Vision Loss Resolved by Surgical Resection of Intraosseous Spheno-Orbital Meningioma: A Case Report and Literature Review

Background and Importance  We present a case of a patient with a residual intraosseous sphenoid wing meningioma presenting with proptosis, orbital pain, and monocular vision loss for 8 months who underwent decompression of the optic canal, orbital contents, and orbital reconstruction resulting in significant improvement in her vision loss with full resolution of proptosis and orbital pain. Clinical Presentation  A 43-year-old female presented with a 1 year history of headache, peri-orbital pain, proptosis, and severe vision loss. She had previously undergone subtotal resection of a large Simpson Grade 1 spheno-orbital meningioma 3 years prior at an outside institution. Workup at our institution revealed hyperostosis of the left greater wing of the sphenoid bone and narrowing of the optic canal along with bony enhancement concerning for residual tumor. The patient was given the recommendation from outside institutions for radiation, presumably due to the chronicity of her visual loss. Our institution recommended resection of the residual osseous tumor with orbital reconstruction. Less than 2 weeks after surgery, the patient noted significant improvement in orbital pain and vision. At 3 months, she had regained full and symmetric orbital appearance with no orbital pain. Her visual acuity improved to 20/30 with full visual fields. Conclusion  Surgical decompression of the optic canal and orbital contents for tumor related sphenoid wing hyperostosis should be strongly considered, despite an extended duration of visual change and loss. This case report shows that vision can be significantly restored even after symptoms have been present for greater than 6 months.

Type III Intraosseous Meningioma Invading Superior Sagittal Sinus and Skull Periosteum

Type III intraosseous meningioma is a very rare type of meningioma with extracranial extension. Herein, the author reported a case of type IIIC intraosseous meningioma with invasion of the superior sagittal sinus and skull periosteum. A 67-year-old woman was admitted to our hospital due to a mass on the left frontoparietal region for 4 years. Magnetic resonance imaging showed a skull tumor with invasion of the superior sagittal sinus. After partial resection of the tumor, pathological and immunohistochemical staining revealed that the epithelial meningioma derived from skull involved the skull periosteum. There was no enlargement of residual parasagittal tumor after 1 year of follow-up. The intraosseous meningioma in the present case was a rare benign tumor with good prognosis after surgery.

Pediatric Orbital Roof Intradiploic Meningioma Operated by Eyebrow Incision

INTRODUCTION

Primary intradiploic meningiomas account for <1% of all osseous calvarial lesions and are categorized as bone tumors. They are frequently observed in the frontotemporal region of the calvarium, anterior cranial fossa, and orbit. We present a case of intradiploic meningioma of the orbital roof, which is rarely observed in the pediatric age-group; it was surgically treated with a unique minimally invasive approach.

CASE PRESENTATION

A 16-year-old male with chief complaints of headache on the right side for approximately 1 year was presented to our clinic. Cranial MRI revealed an intradiploic mass with homogeneous, hypointense contrast patterns on the T1W and T2W images of the right orbital roof. A skin incision was made through the right eyebrow, and the frontal sinus anterior wall was opened by craniotomy. Gross total resection was achieved by reaching the tumor present in the orbital roof. The mass was characterized as psammomatous meningioma by a pathological examination.

DISCUSSION/CONCLUSION

In cranial oncologic surgery, lesion localization and possible pathological diagnosis are essential for the determination of the correct surgical technique. In particular, in pediatric cases, selecting a method that will reduce the need for transfusion, shorten the surgical time, minimize the chances of facial deformity, and facilitate postoperative care will ensure compliance with the correct and appropriate treatment process.

Pathology of meningiomas

Meningiomas are a diverse group of neoplasms that exhibit a wide range of morphologies and clinical behavior. They are generally accepted to originate from arachnoid cap cells within the leptomeninges. Classic histologic features include whorl formations, psammoma bodies, nuclear holes, and nuclear pseudoinclusions. Meningiomas are classified as benign, atypical, or anaplastic (grades I, II, or III) based on histologic features including mitotic activity, brain invasion, and presence of other minor criteria. There are numerous histologic variants of meningiomas, and some are associated with worse clinical outcomes and therefore are assigned a higher grade. The majority of meningiomas show diffuse positivity for vimentin and epithelial membrane antigen, supporting the dual mesenchymal and epithelial nature of meningothelial cells. The presence of an elevated proliferation index (as measured by Ki-67 immunohistochemical stain) and loss of progesterone receptor expression are associated with the higher grade. Pathologic features including histologic variants, grading criteria, and ancillary tests such as special and immunohistochemical stains are discussed.

Theragnostic Use of Radiolabelled Dota-Peptides in Meningioma: From Clinical Demand to Future Applications

Meningiomas account for approximately 30% of all new diagnoses of intracranial masses. The 2016 World Health Organization's (WHO) classification currently represents the clinical standard for meningioma's grading and prognostic stratification. However, watchful waiting is frequently the chosen treatment option, although this means the absence of a certain histological diagnosis. Consequently, MRI (or less frequently CT) brain imaging currently represents the unique available tool to define diagnosis, grading, and treatment planning in many cases. Nonetheless, these neuroimaging modalities show some limitations, particularly in the evaluation of skull base lesions. The emerging evidence supporting the use of radiolabelled somatostatin receptor analogues (such as dota-peptides) to provide molecular imaging of meningiomas might at least partially overcome these limitations. Moreover, their potential therapeutic usage might enrich the current clinical offering for these patients. Starting from the strengths and weaknesses of structural and functional neuroimaging in meningiomas, in the present article we systematically reviewed the published studies regarding the use of radiolabelled dota-peptides in surgery and radiotherapy planning, in the restaging of treated patients, as well as in peptide-receptor radionuclide therapy of meningioma.

Clivus Intraosseous Meningioma Mimicking Chordoma

A 78-year-old woman with progressive worsening vertigo and new onset of diplopia. Neurological examination revealed bilateral abducens nerve paralysis and gait disturbance with truncal ataxia. Neuroimaging revealed a mass lesion within the clivus with brain stem compression. The patient was operated with provisional diagnosis of clivus chordoma by neuro-navigation-guided extended endoscopic endonasal approach. Subtotal resection of the tumor was achieved with no intra- or postoperative complications. Histopathologic examination revealed intraosseous meningioma (WHO grade I). To the authors' best knowledge this is the first case reporting clivus site of intraosseous meningioma.

Multiple primary intraosseous meningioma mimicking fibrous dysplasia: a case report

Primary intraosseous meningioma (PIM) is a rare subtype of primary extradural meningiomas. These rare ectopic meningiomas have been usually reported in the frontotemporal regions of the calvarium, orbits, and anterior cranial fossa. We report a case with bilateral tumors located in frontoparietal regions of calvarium. Our initial diagnosis was fibrous dysplasia but the lesions were seen to expand under follow-up. One was resected and the histopathological diagnosis was PIM. This is the second reported case of multiple PIM.

A contemporary and a historical patient with an ectopic meningioma

Introduction: Ectopic meningiomas are rare tumors which can be encountered by all surgical specialties. Patients and methods: We report on two different cases, a contemporary one and a historical one, highlighting the diversity of clinical presentations and prognoses of these lesions. Furthermore epidemiological aspects, clinical features, and diagnostic and therapeutic work-up in patients with an ectopic meningioma are reviewed. Results: Typically, ectopic meningiomas present as gradually expanding lesions, causing a variety of symptoms by their mass effect. Diagnosis is based on histological characteristics, which are similar to those of intracranial meningiomas. Treatment is primarily surgical. Conclusions: The cases we report are at different ends of the clinical and prognostic spectrum. Therapeutic options for different clinical scenarios are discussed.