From the radiologic pathology archives: mass lesions of the dura: beyond meningioma-radiologic-pathologic correlation

Differential diagnosis of intracranial solitary fibrous tumor and high-grade meningioma based on CT and MRI features

BackgroundISFT and HGM exhibit similar imaging characteristics, but their distinct behaviors and treatments necessitate accurate preoperative imaging for optimal management.PurposeTo evaluate conventional CT and MRI in differentiating ISFT from HGM.MethodsRetrospective analysis of clinical data, CT, and MRI images from 31 ISFT and 50 HGM patients confirmed by pathology. Various imaging features were examined, including tumor size, shape (lobulated or round), base width (narrow or broad), presence of cystic necrosis, calcification, signal intensity on T1- and T2-weighted MRI, intravascular flowing-void signs, peritumoral edema, CT attenuation values on non-enhanced and enhanced scans, and adjacent bone destruction. Chi-square tests, t-tests, ROC curves, and multivariate logistic regression were used to establish predictive models. A nomogram illustrated the final model.ResultsISFT onset age was ≤48.5 years, with a maximum tumor diameter of ≥4.5 cm. Features included lobulated appearance, narrow base, cystic necrosis, absence of calcification, low T1-weighted MRI signal, intravascular flowing-void signs, peritumoral edema, CT value ≤51.7 Hu on non-enhanced and ≥107.6 Hu on enhanced scans, and adjacent bone destruction. Combining tumor diameter, vascular flowing void, enhanced CT value, and absence of calcification yielded 92.0% sensitivity and 90.3% specificity for ISFT diagnosis.ConclusionAge and imaging characteristics effectively differentiate ISFT from HGM, particularly with a tumor diameter ≥4.5 cm, vascular flowing-void signals, absence of calcification, and enhanced CT value ≥107.6 Hu. A nomogram shows good predictive efficacy.

Deep learning radiomic nomogram outperforms the clinical model in distinguishing intracranial solitary fibrous tumors from angiomatous meningiomas and can predict patient prognosis

OBJECTIVES

To evaluate the value of a magnetic resonance imaging (MRI)-based deep learning radiomic nomogram (DLRN) for distinguishing intracranial solitary fibrous tumors (ISFTs) from angiomatous meningioma (AMs) and predicting overall survival (OS) for ISFT patients.

METHODS

In total, 1090 patients from Beijing Tiantan Hospital, Capital Medical University, and 131 from Lanzhou University Second Hospital were categorized as primary cohort (PC) and external validation cohort (EVC), respectively. An MRI-based DLRN was developed in PC to distinguish ISFTs from AMs. We validated the DLRN and compared it with a clinical model (CM) in EVC. In total, 149 ISFT patients were followed up. We carried out Cox regression analysis on DLRN score, clinical characteristics, and histological stratification. Besides, we evaluated the association between independent risk factors and OS in the follow-up patients using Kaplan-Meier curves.

RESULTS

The DLRN outperformed CM in distinguishing ISFTs from AMs (area under the curve [95% confidence interval (CI)]: 0.86 [0.84-0.88] for DLRN and 0.70 [0.67-0.72] for CM, p < 0.001) in EVC. Patients with high DLRN score [per 1 increase; hazard ratio (HR) 1.079, 95% CI: 1.009-1.147, p = 0.019] and subtotal resection (STR) [per 1 increase; HR 2.573, 95% CI: 1.337-4.932, p = 0.004] were associated with a shorter OS. A statistically significant difference in OS existed between the high and low DLRN score groups with a cutoff value of 12.19 (p < 0.001). There is also a difference in OS between total excision (GTR) and STR groups (p < 0.001).

CONCLUSION

The proposed DLRN outperforms the CM in distinguishing ISFTs from AMs and can predict OS for ISFT patients.

CLINICAL RELEVANCE STATEMENT

The proposed MRI-based deep learning radiomic nomogram outperforms the clinical model in distinguishing ISFTs from AMs and can predict OS of ISFT patients, which could guide the surgical strategy and predict prognosis for patients.

KEY POINTS

Distinguishing ISFTs from AMs based on conventional radiological signs is challenging. The DLRN outperformed the CM in our study. The DLRN can predict OS for ISFT patients.

Machine Learning Analysis of Single-Voxel Proton MR Spectroscopy for Differentiating Solitary Fibrous Tumors and Meningiomas

Solitary fibrous tumor (SFT), formerly known as hemangiopericytoma, is an uncommon brain tumor often confused with meningioma on MRI. Unlike meningiomas, SFTs exhibit a myoinositol peak on magnetic resonance spectroscopy (MRS). This study aimed to develop automated classifiers to distinguish SFT from meningioma grades using MRS data from a 26-year patient cohort. Four classification tasks were performed on short echo (SE), long echo (LE) time, and concatenated SE + LE spectra, with datasets split into 80% training and 20% testing sets. Sequential forward feature selection and linear discriminant analysis identified features to distinguish between meningioma Grade 1 (Men-1), meningioma grade 2 (Men-2), meningioma grade 3 (Men-3), and SFT (the 4-class classifier); Men-1 from Men-2 + 3 + SFT; meningioma (all) from SFT; and Men-1 from Men-2 + 3 and SFT. The best classifier was defined by the smallest balanced error rate (BER) in the testing phase. A total of 136 SE cases and 149 LE cases were analyzed. The best features in the 4-class classifier were myoinositol and alanine at SE, and myoinositol, glutamate, and glutamine at LE. Myoinositol alone distinguished SFT from meningiomas. Differentiating Men-1 from Men-2 was not possible with MRS, and combining higher meningioma grades did not improve distinction from Men-1. Notably, combining short and long echo times (TE) enhances classification performance, particularly in challenging outlier cases. Furthermore, the robust classifier demonstrates efficacy even when dealing with spectra of suboptimal quality. The resulting classifier is available as Supporting Information of the publication. Extensive documentation is provided, and the software is free and open to all users without a login requirement.

Long-Term Clinical Landscapes of Spinal Hypertrophic Pachymeningitis With Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis

BACKGROUND AND OBJECTIVES

Spinal hypertrophic pachymeningitis (HP) is an extremely rare disorder characterized by the thickening of the spinal dura mater, which harbors distinct repertoires of immune cells due to the unique partitioning of the arachnoid blood-CSF barrier. The objectives were to identify the pathogenesis and therapeutic strategies for spinal HP.

METHODS

This retrospective cohort study analyzed the clinical and pathologic profiles of patients with idiopathic/immune-mediated HP including spinal HP.

RESULTS

Among 61 patients with idiopathic/immune-mediated HP, all 6 Japanese patients with spinal HP, with a median observation period of 88.8 months, were myeloperoxidase (MPO)-anti-neutrophil cytoplasmic antibody (ANCA)-seropositive. The MPO-ANCA+ spinal HP cohort had the following characteristics: (1) a predominance of older women; (2) all patients were classified as having microscopic polyangiitis based on the 2022 American College of Rheumatology/European League Against Rheumatism criteria; (3) 83% of patients developed subacute/chronic myelopathy due to extramedullary spinal cord compression; (4) 50% of patients had lesion extension to the epidural compartment and vertebral column; (5) 50% of patients presented with chronic sinusitis, otitis media, or mastoiditis; (6) 33% of patients had involvement of the lower airways or kidneys; (7) a higher disease activity of the nervous system was noted based on the Birmingham Vasculitis Activity Score (BVAS), in contrast to MPO-ANCA+ cranial HP; (8) granulomatous inflammation with myofibroblasts, immune cells including granulocytes, and B-cell follicle-like structures were observed in the thickened dura mater; (9) immunotherapies (with or without surgical decompression) were effective in reducing the modified Rankin Scale score and reduced BVAS during the first active insults; (10) combined immunotherapies with glucocorticoids and cyclophosphamide/rituximab helped in reducing relapses in the long term; and (11) surgical decompression, including laminectomy and duraplasty, was necessary for compressive myelopathy. These data suggest that MPO-ANCA+ spinal HP shares common features with MPO-ANCA+ cranial HP (1, 2, 6, 8, 9, and 10), but also has unique clinical features (3, 4, 5, 7, and 11).

DISCUSSION

Our findings highlight the significant pathogenic role of ANCA in spinal HP. MPO-ANCA+ spinal HP, as an organ-threatening disease, should be positioned as having unique characteristics, whether limited to the CNS or as part of a generalized form in ANCA-associated vasculitis.

Endoscopic Transnasal Transclival Removal of a Giant Hemangiopericytoma Involving the Clivus and C1-C2 Vertebrae: A Clinical Case and Literature Review

Hemangiopericytomas, or solitary fibrous tumors (SFT), are neoplasms of mesenchymal origin that are quite rare in oncological practice. These tumors often grow to large sizes before the onset of clinical symptoms, and in imaging studies, they closely resemble meningiomas, making diagnosis challenging. When treating intracranial hemangiopericytoma, it is necessary to ensure the most radical removal followed by radiation therapy. We present a rare case of transnasal transclival subtotal removal of a giant hemangiopericytoma/SFT of the craniovertebral junction and the C1-C2 vertebral level, not previously described in the literature. Based on the results of the literature review, it was determined that an accurate diagnosis during the instrumental and morphological examination is crucial for the future outcome of a patient with intracranial hemangiopericytoma, as confirmed in the presented case.

Epstein-Barr Virus-Associated Smooth-Muscle Tumor of the Brain

Epstein-Barr virus, a herpesvirus, has been associated with a variety of cancers, including Burkitt, Hodgkin, and non-Hodgkin lymphomas; posttransplant lymphoproliferative disorders; gastric carcinoma; and nasopharyngeal carcinoma, in both immunocompetent and immunocompromised individuals. Previous studies have established a connection between Epstein-Barr virus and the development of smooth-muscle tumors. Smooth-muscle tumors of the brain are very rare and are often misdiagnosed as meningiomas on imaging. To our knowledge, advanced imaging findings such as MR perfusion of smooth-muscle tumors of the brain have never been reported. We describe the radiologic and pathologic features of the Epstein-Barr virus-associated smooth-muscle tumors of the brain in a person with newly diagnosed advanced HIV.

Bench-to-bedside imaging in brain metastases: a road to precision oncology

Radiology has seen tremendous evolution in the last few decades. At the same time, oncology has made great strides in diagnosing and treating cancer. Distant metastases of neoplasms are being encountered more often in light of longer patient survival due to better therapeutic strategies and diagnostic methods. Brain metastasis (BM) is a dismal manifestation of systemic cancer. In the present scenario, magnetic resonance imaging (MRI), computed tomography (CT) and positron emission tomography (PET) are playing a big role in providing molecular information about cancer. Lately, molecular imaging has emerged as a stirring arena of dynamic imaging techniques that have enabled clinicians and scientists to noninvasively visualize and understand biological processes at the cellular and molecular levels. This knowledge has impacted etiopathogenesis, detection, personalized treatment, drug development, and our understanding of carcinogenesis. This article offers insight into the molecular biology underlying brain metastasis, its pathogenesis, imaging protocols, and algorithms. It also discusses disease-specific molecular imaging features, focusing on common tumors that spread to the brain, such as lung, breast, colorectal cancer, melanoma, and renal cell carcinoma. Additionally, it covers various targeted treatment options, criteria for assessing treatment response, and the role of artificial intelligence in diagnosing, managing, and predicting prognosis for patients with brain metastases.

Brain Tumor Imaging: Review of Conventional and Advanced Techniques

Approaches to central nervous system (CNS) tumor classification and evaluation have undergone multiple iterations over the past few decades, in large part due to our growing understanding of the influence of genetics on tumor behavior and our refinement of brain tumor imaging techniques. Computed tomography and magnetic resonance imaging (MRI) both play a critical role in the diagnosis and monitoring of brain tumors, although MRI has become especially important due to its superior soft tissue resolution. The purpose of this article will be to briefly review the fundamentals of conventional and advanced techniques used in brain tumor imaging. We will also highlight the applications of these imaging tools in the context of commonly encountered tumors based on the most recently updated 2021 World Health Organization (WHO) classification of CNS tumors framework.

Immune-Mediated Hypertrophic Pachymeningitis and its Mimickers: Magnetic Resonance Imaging Findings

Hypertrophic pachymeningitis (HP) is a rare and chronic inflammatory disorder presenting as localized or diffuse thickening of the dura mater. It can be idiopathic or an unusual manifestation of immune-mediated, infectious, and neoplastic conditions. Although some cases may remain asymptomatic, HP can lead to progressive headaches, cranial nerve palsies, hydrocephalus, and other neurological complications, which makes its recognition a fundamental step for prompt treatment. Regarding the diagnosis workup, enhanced MRI is the most useful imaging method to evaluate dural thickening. This article addresses the MR imaging patterns of immune-mediated HP, including immunoglobulin G4-related disease, neurosarcoidosis, granulomatosis with polyangiitis, rheumatoid pachymeningitis, and idiopathic HP. The main infectious and neoplastic mimicking entities are also discussed with reference to conventional and advanced MR sequences.

Imaging of Lymphomas Involving the CNS: An Update-Review of the Full Spectrum of Disease with an Emphasis on the World Health Organization Classifications of CNS Tumors 2021 and Hematolymphoid Tumors 2022

Lymphomas of the CNS are the second most frequent primary brain malignancy in adults after gliomas. Presurgical suspicion of lymphoma greatly impacts patient management. The radiologic features of this tumor have been widely covered in the literature for decades, but under current classifications, mainly corresponding to the most common presentations of the most frequent type: primary diffuse large B-cell lymphoma of the CNS. Nevertheless, rarer presentations of this specific lymphoma and of other World Health Organization lymphoma subtypes with different imaging features are rarely treated. Moreover, important advances in imaging techniques, changing epidemiologic factors with relevant impact on these tumors (eg, immunodeficiency/dysregulation), and recent updates of the World Health Organization Classification of CNS Tumors 2021 and Hematolymphoid Tumors 2022 may have rendered some accepted concepts outdated. In this article, the authors aim to fulfill a critical need by providing a complete update-review, emphasizing the latest clinical-radiologic features of the full spectrum of lymphomas involving the CNS.

Usefulness of a Rim-Enhancing Pattern on the Contrast-Enhanced 3D-FLAIR Sequence and MRI Characteristics for Distinguishing Meningioma and Malignant Dural-Based Tumor

BACKGROUND AND PURPOSE

Meningiomas are the most common type of extra-axial dural-based tumors; however, malignant dural-based tumors can mimic meningiomas on imaging. The aim of this study was to determine the efficacy of differentiating meningiomas from malignant dural-based tumors by using rim-enhancement patterns on a contrast-enhanced FLAIR sequence and MR imaging characteristics.

MATERIALS AND METHODS

This retrospective study included 102 patients with meningiomas and 31 patients with malignant dural-based tumors who underwent pretreatment MR imaging. The rim-enhancement patterns on contrast-enhanced FLAIR and MR imaging characteristics, including the dural tail sign, hyperostosis, bony destruction, leptomeningeal enhancement, peritumoral edema, T2-weighted signal intensity, and tumor enhancement were evaluated.

RESULTS

Complete rim enhancement of the tumor-brain interface on contrast-enhanced FLAIR (contrast-enhanced-FLAIR rim sign) was present in most meningiomas (91/102, 89.2%) and at significantly greater frequency than in malignant dural-based tumors (2/31, 6.5%) (P  < .001). Complete contrast-enhanced FLAIR rim enhancement provided high sensitivity (89.2%), specificity (93.5%), and accuracy (90.2%) for diagnosing meningioma. Additionally, hyperostosis was an MR imaging characteristic that suggested a diagnosis of meningioma. In contrast, bony destruction with cortical breakthrough and leptomeningeal enhancement suggested malignant dural-based tumors. There were limitations of meningiomas of <2.0 cm or at cavernous sinus locations that did not demonstrate contrast-enhanced FLAIR rim enhancement.

CONCLUSIONS

The rim-enhancement pattern on contrast-enhanced FLAIR could help differentiate meningiomas and malignant dural-based tumors. The presence of complete rim enhancement on contrast-enhanced FLAIR was a robust predictive sign for meningioma.

Preoperative prediction and histological stratification of intracranial solitary fibrous tumours by machine-learning models

AIM

To explore the effectiveness and feasibility of machine-learning models based on magnetic resonance imaging (MRI) radiomics features in differentiating intracranial solitary fibrous tumour (ISFT) from angiomatous meningioma (AM) and stratifying ISFT histologically.

MATERIALS AND METHODS

This study retrospectively recruited 268 patients with a histological diagnosis of ISFT (n=120) or AM (n=148), and 116 of the ISFT patients were used for stratified analysis of histological grade. The radiomics features were extracted from axial T1-weighted imaging (WI), T2WI and contrast-enhanced T1WI sequences. All patients were assigned randomly to the training group and test group in a ratio of 7:3. The models were optimised by 10-fold cross-validation in the training group, and the independent test group was used for further testing of the models. The performances of machine-learning models based on radiomics, clinical, and fusion features in predicting and stratifying ISFT were evaluated.

RESULTS

ISFT and AM differed significantly in terms of age, tumour shape, enhancement pattern, and margin. There was no significant difference in the clinical characteristics between World Health Organization (WHO) grade II and WHO grade III ISFT. When used to differentiate ISFT from AM, the area under the curve (AUC) values of the machine-learning models based on radiomics, clinical, and fusion features in the test group were 0.917, 0.923 and 0.950, respectively. When used for histological stratification of ISFT, the model based on the radiomics signature achieved an AUC value of 0.786 in the test group.

CONCLUSIONS

Machine-learning models can contribute in the prediction and histological stratification of ISFT non-invasively, which can help clinical differential diagnosis and treatment decisions.

Solitary fibrous tumor of the central nervous system invading and penetrating the skull: A case report

Solitary fibrous tumor (SFT) of the central nervous system is a rare spindle cell tumor of mesenchymal origin. The present study reports the case of a 44-year-old male patient with SFT. Magnetic resonance imaging demonstrated that the majority of the intracranial tumors exhibited uneven low signals on T1-weighted imaging (T1WI) and low mixed signals on T2WI, and there was an enhancement on enhanced scanning. Furthermore, the distal part of the left occipital lobe exhibited hypersignals on T1WI and T2WI, and this was significantly enhanced following enhanced scanning. The lower part of the scalp exhibited low signals on T1WI and high signals on T2WI, and there was no notable enhancement following enhanced scanning. Magnetic resonance spectroscopy demonstrated an elevated choline/creatine peak in the solid part of the tumor. Under the microscope, the tumor exhibited characteristic 'staghorn-shaped' blood vessels. As SFT is difficult to differentially diagnose via imaging, immunohistochemical analysis of CD34, vimentin and signal transducer and activator of transcription 6 was performed for the definitive diagnosis of SFT. Of note, surgical resection was the preferred treatment for SFT; however, due to the rarity of the tumor, subsequent adjuvant therapy and prognosis require further investigation.

Sporadic Cerebellar Hemangioblastoma With Strong SSTR Expression on 68 Ga-DOTANOC PET/CT

ABSTRACT

Sporadic cerebellar hemangioblastomas are rare with majority of these tumors presenting as a part of von Hippel-Lindau syndrome. We demonstrate an unusual case of a symptomatic sporadic cerebellar hemangioblastoma mimicking a meningioma on MRI and 68 Ga-DOTANOC PET imaging.

Dural lymphoma misdiagnosed as subdural hematoma following head trauma after an episode of syncope

Primary dural lymphoma is a rare subtype of primary central nervous system lymphoma. Primary dural lymphoma may be radiologically misdiagnosed as it shares similar imaging characteristics with several pathologies, including meningiomas and subdural or epidural hematomas. We present a patient who was originally diagnosed with a subdural hematoma following a syncopal episode on computed tomography. Follow-up magnetic resonance imaging of the brain demonstrated heterogeneously enhancing dural-based mass overlying the left frontoparietal convexity associated with bidirectional dural tails, suggestive of a malignant meningioma. Neurosurgical histopathology revealed marginal zone B-cell lymphoma. This case represents the potential difficulty in diagnosing primary dural lymphoma, especially in the setting of uncertain clinical history and obscured imaging features.

Solitary Isolated Dural Metastasis From Lung Adenocarcinoma Mimicking Meningioma

ABSTRACT

Solitary isolated dural metastasis is extremely rare. Distinguishing solitary dural metastasis from meningioma based on radiological findings can be challenging. We describe MRI and FDG PET/CT findings in 2 cases of histologically proved solitary isolated dural metastasis from lung adenocarcinoma. Enhanced brain MRI of the 2 cases showed parafalcine extra-axial, dural-based tumors with hypervascularity mimicking meningioma. Preoperative FDG PET/CT was performed in one case with a known history of lung adenocarcinoma showing intense FDG uptake of the parafalcine tumor. Postoperative FDG PET/CT was performed in the other case showing solitary lung tumor, suggestive of the primary tumor.

Different facets of intracranial central nervous system lymphoma and its imaging mimics

Lymphomas of the central nervous system (CNS) are broadly classified into primary CNS lymphoma (PCNSL) and secondary CNS lymphoma (SCNSL). PCNSL refers to lymphoma restricted to the brain, leptomeninges, spinal cord, or eyes without evidence of it outside the CNS at primary diagnosis, while SCNSL refers to secondary CNS involvement by systemic lymphoma. The brain is the most common site of involvement and intracranial CNS lymphoma has a highly variable imaging appearance and varies according to the patient’s clinical profile and immunity. This pictorial essay aims to illustrate the different facets of intracranial CNS lymphomas on neuroimaging. This enables radiologists to be familiarized with their key diagnostic features and differentiate from their differential diagnoses, leading to early diagnosis, and treatment.

Solitary fibrous tumor of the pineal region in the elderly: A case report

INTRODUCTION

Solitary fibrous tumor (SFT) is a mesenchymal tumor with spindle cells that is often detected in the subcutaneous area and rarely in the central nervous system. Intracranial SFTs rarely occur in individuals older than 80 years, and there are only a few cases reports involving the pineal region.

PRESENTATION OF CASE

The present case was an 80-year-old man with lightheadedness, headache, and vomiting. Magnetic resonance imaging showed a tumor in the pineal region extending along the falx and tentorium cerebelli with homogenous enhancement. Subtotal resection was performed via the occipital transtentorial approach. A histopathological examination showed the proliferation of oval- to spindle-shaped tumor cells with bland nuclei arranged in a haphazard pattern and accompanied by staghorn-like branching vessels. Immunohistochemically, tumor cells were positive for CD34 (focal), CD99, and STAT6, but negative for epithelial membrane antigen (EMA) and S-100. Based on these findings, the tumor was diagnosed as SFT (WHO grade I).

DISCUSSION

Although difficulties are associated with differentiating SFT from meningioma on imaging, recurrence and metastasis are more common with SFT than with meningioma; therefore, histological and immunohistochemical analyses are important. A correlation has been reported between postoperative adjuvant radiotherapy and longer progression-free survival; however, this needs to be confirmed in further studies.

CONCLUSION

SFT involving the pineal region is rare in the elderly, but needs to be considered as a preoperative diagnosis. Since high rates of postoperative recurrence and metastasis have been reported, long-term follow-ups are required after surgery.

Case Report: Creeping Growth in Lymphoplasmacyte-Rich Meningioma-A Radiologic Variant

Lymphoplasmacyte-rich meningioma (LRM) is a rare histologic subtype of meningioma. Creeping-growth pattern is uncommon in meningioma, and the mechanism is unclear. Here, we report a 44-year-old man presented with extremities weakness for 2 months and incontinence for 2 weeks. Head and neck MRI revealed diffuse creeping-growth nodular meningeal masses with skull base, tentorium, sella area, and C1-6 vertebral plane involvement. An operation was carried out, cervical and lower clivus part of the lesion was resected, but gross total resection could not be achieved due to the widespread lesions. Pathologic examination revealed the diagnosis of LRM. The patient is free from progression clinically 3 months postoperatively. We also conducted a systematic literature review about LRM with creeping-growth pattern. A total of only nine cases (including the present case) of creeping-growth LRMs were included and analyzed in terms of clinical manifestations, radiological features, treatment, and outcome. LRMs show a higher rate (7.5%) of creeping-growth pattern than other types of meningiomas. The average creeping length of all creeping-growth LRMs was 11.4 ± 10.9 cm (range, 3–30 cm). Most cases (66.7%) had obvious peritumoral edema. Total removal rate is low (33.3%), and two of them (22.2%) received biopsy, followed by steroids treatment (or further immunosuppressive drugs therapy) and radiotherapy. The recurrence rate is higher than conventional LRMs (22.2 vs. 11.3%), and one patient (11.1%) died 11 months after treatment. Creeping-growth pattern in LRM may be considered as a general radiologic variant. The recurrence rate is higher compared with LRM with round/swelling pattern. We speculated that the pathogenesis of creeping growth in LRM may be associated with damage of lymphatic systems of the central nervous system.

Primary extraosseous dural chondrosarcoma: a case report

BACKGROUND

Dural chondrosarcoma is a very rare intracranial tumor, given that meninges do not normally contain cartilaginous tissue from which it can originate. We present a case of primary extraosseous dural chondrosarcoma.

CASE PRESENTATION

A 48-year-old woman presented to our tertiary center neurosurgery consultation with progressive headache, vomiting, vertigo, and gait instability of 5 months' duration. An initial brain CT revealed a large parietal mass with gross calcifications and subtle hyperostosis of the inner table. Subsequent brain MRI showed a heterogeneous expansive lesion with a honey-comb enhancement. Discussion of intra- or extra-axial location was warranted, and finally, initial presurgical suspicion of meningioma arose although some atypical imaging features were detected. The differential diagnosis included solitary fibrous tumor-hemangiopericytoma and dural metastasis. Total resection of the lesion was performed, extra-axial origin was confirmed, and pathology resulted in a primary dural chondrosarcoma.

CONCLUSION

The importance of this case presentation lies in the unusual nature of the final diagnosis, the brief literature review and differential diagnosis with emphasis on imaging pearls, as well as the useful reminder for physicians to consider less frequent diseases when key findings do not unambiguously lead to the usual suspects.

Cervical solitary fibrous tumor: case report and literature review

Solitary fibrous tumors (SFTs) are rare neoplasms in the spinal canal. There are few studies addressing SFT/hemangiopericytomas with no distinctive clinical characteristics, no conclusive radiological findings or even a well-defined best treatment strategy. We described a rare case of cervical SFT/hemangiopericytomas in a young patient with spinal cord compression. There are many differential diagnoses for spinal dural-based masses of which meningiomas are the most common. Surgeons and oncologists should be aware of differentials of dural-based masses in the spinal cord for surgical decision making and to guide treatment.

Misdiagnosis and Delay of Diagnosis in Hemorrhagic Meningioma: A Case Series and Review of the Literature

OBJECTIVE

To evaluate the clinicoradiologic characteristics of hemorrhagic meningiomas (HMs) that are missed or misdiagnosed on radiologic imaging studies.

METHODS

Clinical and radiologic data from 6 patients with HM who were initially misdiagnosed were collected and recorded respectively. In addition, we performed a literature review for misdiagnosed HM and summarized the results.

RESULTS

Five of the 6 patients with misdiagnosed HM were female, and 1 was male. Both computed tomography (CT) and magnetic resonance imaging were performed in 4 patients, and CT alone was performed in 2. On CT, the HM was heterogeneously hyperdense in 5 patients and isodense in 1 patient. In all 4 patients who underwent magnetic resonance imaging, the HM was mixed iso- and hypointense on T1-weighted imaging and heterogeneously hyperintense on T2-weighted imaging. Marked heterogeneous contrast enhancement was observed in 2 patients, strong rim enhancement in 1, and peripheral enhancement in 1. The dural tail sign was seen in only 1 patient. The initial radiologic misdiagnoses were subdural hematoma (n = 1), malignant glioma (n = 1), ruptured arterial aneurysm (n = 1), metastasis (n = 2), and uncertain (n = 1). In the literature review, 22 cases of HM diagnostic error were collected. The main misdiagnoses were subdural hematoma (27.3%), traumatic hematoma (13.6%), vascular anomaly (13.6%), malignant glioma (4.5%), and metastasis (4.5%).

CONCLUSIONS

Our study showed that in patients with HM with inadequate imaging evaluation, a small tumor associated with massive hematoma and atypical imaging features was more likely to be misdiagnosed.

Primary CNS Extranodal Marginal Zone B-Cell Lymphoma: A Case Series of 2 Patients Treated with External Beam Radiation Therapy

Primary CNS extranodal marginal zone B-cell lymphoma (MZBL) is a rare low-grade non-Hodgkin lymphoma characterized predominantly by small B cells, plasma cells, monocytoid cells, and scattered large immunoblasts. As a slow-growing tumor that remains localized, primary CNS MZBL carries an excellent clinical prognosis. Here, we report two cases of primary CNS MZBL successfully treated using external beam radiation therapy along with a literature review.

Primary Intracranial Leiomyosarcoma Secondary to Glioblastoma: Case Report and Literature Review

Background

Leiomyosarcoma is a highly malignant soft-tissue sarcoma with a poor prognosis. In recent years, treatment for leiomyosarcoma has not shown much progress. Primary intracranial leiomyosarcoma (PILMS) is a much rarer type of neoplasm, which occurs more frequently in immunocompromised patients. PILMS cases reported in the literature are scarce and treatment strategy and prognosis are still under debate. In this study, a case of PILMS secondary to the total resection of giant cell glioblastoma is reported.

Case Description

A 38-year-old male was hospitalized with a three-month history of a temporal opisthotic bump. His medical history included a total resection of a tumor located in the right temporal lobe performed 4 years earlier. Pathological examination led to a diagnosis of giant cell glioblastoma, and the patient underwent postoperative chemotherapy with temozolomide for 6 weeks plus simultaneous radiotherapy with 63.66 Gary. Four years later, during regular follow-up, a preoperative MRI brain scan resulted in a well-defined signal pointing out two nodule-like features located at the right temporal lobe and subcutaneous soft tissue, respectively, and near the area where the previous giant cell glioblastoma was located. The mass was completely removed by a transtemporal approach and postoperative pathology revealed that the mass was a leiomyosarcoma. The patient underwent postoperative radiotherapy and no recurrence occurred until now.

Conclusions

To date, research on soft-tissue sarcoma, especially PILMS, has not made much progress, and a limited number of studies have provided few details on the management of PILMS. The treatment of choice for PILMS is aggressive multimodal treatment based on total tumor resection and radiotherapy. Moreover, systemic treatment with chemotherapy and targeted therapy, such as olaratumab, as well as further research still needs to be performed as many questions are left unanswered. To our knowledge, this is the first report on a case of PILMS secondary to glioblastoma, which might serve as a potential reference for clinicians and clinical studies.

Pitfalls in the diagnosis of subdural hemorrhage - Mimics and uncommon causes

PURPOSE

Subdural hemorrhage (SDH), the accumulation of blood between the dura and arachnoid mater, is one of the most commonly encountered traumatic findings in emergency radiology setting. The purpose of this essay is to review the pitfalls in the diagnosis of SDH including a) mimics on CT imaging and b) etiology other than accidental trauma. We describe several entities that closely mimic SDH on non-contrast CT scans. A knowledge of these mimics is essential in the emergency setting since overdiagnosis of SDH can lead to unnecessary hospital admissions, potentially invasive procedures, or even delay in necessary treatment. The mimics of SDH on non-contrast head CT include: PATHOLOGIC ENTITIES IATROGENIC MIMICS ANATOMIC/PHYSIOLOGIC MIMICS ARTIFACTUAL MIMICSWe also briefly review non-accidental and non-traumatic causes of SDH. Although, the most common cause of SDH is accidental trauma, other routinely encountered causes of SDH include coagulopathy, non-accidental trauma, cranial surgery, vascular malformations etc. CONCLUSION: Clinicians dealing with SDH in the emergency setting should consider SDH mimics and less common etiologies of SDH in order to facilitate appropriate patient management.

Intracranial solitary fibrous tumor/hemangiopericytoma mimicking cystic meningioma: A case report and literature review

Intracranial solitary fibrous tumor/hemangiopericytoma (SFT/HPC) is a relatively rare type of tumor that originates from meningeal mesenchyme. A 30-year-old man presented leaning his body to the left and with weakness of his left lower limb. Computed tomography revealed a heterogeneous mass with multiple cystic components and hyperostosis of the right cranial convexity. Magnetic resonance imaging showed the mass was broadly attached to the dura matter with dural tail sign. In addition, the lesion had extensive cystic degeneration and a solid compartment showing low apparent diffusion coefficient values. The patient underwent gross total resection of the intracranial lesion and presented no recurrence within a 12-month follow-up period. Histopathology confirmed SFT/HPC (World Health Organization grade Ⅱ). Although there have been several useful techniques reported to differentiate SFT/HPC from meningioma, in this case the atypical findings for SFT/HPC made it difficult. We report the imaging findings of this case and some literature reviews.

Non-functional recurrent pituitary adenoma with intracranial metastasis-Pituitary carcinoma: A case report and review of the literature

INTRODUCTION

Pituitary carcinomas are rare, with only a few case reports to date. We present a null cell type non-functioning pituitary carcinoma (NFPC) with intracranial metastases and a review of the literature.

CASE REPORT

A 56-year-old male with a history of an aggressive pituitary adenoma was admitted. Initial MRI highlighted a large intracranial mass with leptomeningeal involvement, simulating meningioma. Based on his previous pathology report of the sellar mass, a diagnosis of null cell type non-functioning pituitary carcinoma has been made.

CONCLUSIONS

An aggressive recurrent pituitary tumor with suprasellar and/or cavernous sinus invasion is the main characteristics of the NFPC. Single or multiple enhancing dural-based mass(es) mimicking meningioma is the most common MRI finding. The proof of malignancy is the same histopathological features of the recurrent aggressive pituitary tumor in the metastases. The histology alone is not distinctive in terms of malignancy. Most patients require a combined surgery, radiotherapy and chemotherapy.

Pathological Spectrum of Dura-Based Nonmeningothelial Lesions: 5 Years' Experience from a Tertiary Care Centre

Introduction Nonmeningothelial lesions arising from the dura comprise a wide spectrum of pathologies ranging from neoplastic to infective etiologies. They have overlapping clinical and radiologic findings necessitating histopathological evaluation for the final diagnosis which in turn dictates management and prognosis. Therapeutic strategies are different for each of the lesion. There is scarcity of large case series detailing clinicopathological spectrum of dura-based nonmeningothelial lesions.

Materials and Methods In this study, we analyzed the neuropathological spectrum of dura-based nonmeningothelial lesions diagnosed over a period of 5 years in our tertiary care center.

Results There were 79 cases of dura-based nonmeningothelial lesions constituting 7.3% of all dura-based lesions (age range: 2–75 years; M:F = 2:3). Basal region was more frequently involved than the convexities. On histopathology, neoplastic lesions predominated (92.4%) and included in order of frequency solitary fibrous tumor/hemangiopericytoma (35.6%), gliomas (27.4%), metastasis (27.4%), mesenchymal tumors (4%), primitive neuroectodermal tumor (2.73%), and medulloblastoma (2.73%). Infective lesions were less frequent (7.6%), included fungal infections and Rosai-Dorfman disease.

Conclusion Awareness of the spectrum of nonmeningothelial dural lesions is useful for pathologists as well as the treating surgeon.

Dural-based lesions: is it a meningioma?

PURPOSE

Meningiomas are the most common extra-axial intracranial neoplasms with typical radiological findings. In approximately 2% of cases, histopathological reports reveal different neoplasms or non-neoplastic lesions that can closely mimic meningiomas. We describe radiological features of meningioma mimics highlighting imaging red flags to consider a differential diagnosis.

METHODS

A total of 348 lesions with radiological diagnosis of meningiomas which underwent to surgical treatment or biopsy between December of 2000 and September of 2014 were analyzed. We determined imaging features that are not a typical finding of meningiomas, suggesting other lesions. The following imaging characteristics were evaluated on CT and MRI: (a) bone erosion; (b) hyperintensity on T2WI; (c) hypointensity on T2WI; (d) bone destruction; (e) dural tail; (f) leptomeningeal involvement; (g) pattern of contrast enhancement; (h) dural displacement sign.

RESULTS

We have a relatively high prevalence of meningioma mimics (7.2%). Dural-based lesions with homogeneous contrast enhancement (52%) are easily misdiagnosed as meningiomas. Most lesions mimic convexity (37.5%) or parafalcine (21.9%) meningiomas. We have determined five imaging red flags that can alert radiologists to consider meningioma mimics: (1) bone erosion (22.2%); (2) dural displacement sign (36%); (3) marked T2 hypointensity (32%); (4) marked T2 hyperintensity (12%); (5) absence of dural tail (48%). The most common mimic lesion in our series was hemangiopericytomas, followed by lymphomas and schwannomas.

CONCLUSION

The prevalence of meningioma mimics is not negligible. It is important to have awareness on main radiological findings suggestive of differential diagnosis due to a wide range of differentials which lead to different prognosis and treatment strategies.

Grade III Solitary Fibrous Tumor/Hemangiopericytoma: A Rare Case of a World Health Organization Grade III Anaplastic Hemangiopericytoma

Solitary fibrous tumors (SFTs) and hemangiopericytomas (HPCs) have been combined into a single designation in the most recent World Health Organization (WHO) guidelines as solitary fibrous tumor/hemangiopericytoma (SFT/HPC). These rare intracranial tumors can present as WHO grade I, II, or III tumors, with the risk of recurrence, metastasis, and mortality worsening with higher-grade tumors. We present a case of a patient with a WHO grade III SFT/HPC with an emphasis on the imaging features that help differentiate this type of tumor from meningiomas, which are much more common and can appear similar. Being able to help differentiate these tumors by their imaging appearance is important to help triage and risk-stratify patient management decisions.

Occipital Hemangiopericytoma 10 Years after Initial Manifestation

Teaching Point: Cranial hemangiopericytoma is a rare neoplasm that can be differentiated from meningioma on imaging by its lobulated, mushrooming contours and adjacent osteolysis rather than hyperostosis.

Epstein Barr virus associated smooth muscle tumors in the central nervous system: a case report and systematic review of the literature

PURPOSE

Epstein Barr virus (EBV)-associated smooth muscle tumors (SMT) in the central nervous system are rare tumors. EBV-associated SMT mainly occur in patient with compromised immune status. We report on a case of a HIV positive patient, who developed multiple EBV-SMTs, intracranially and in the spine. We systematically review the literature on the topic.

CASE REPORT

A 46 years old female with HIV was imaged for complaints of headaches for 2 years, when an intracranial lesion was found. The patient was followed with sequential MRI scans before an excision was performed 5 years later. Pathology revealed an EBV-associated SMT. Multiple other lesions appearing in the brain and in the spine over years were treated by stereotactic radiosurgery or by surgery. At the time of this report, the patient is alive under HARRT treatment without recurrence.

METHODS

A systematic PRISMA guided literature research was conducted on the topic reviewing multiple databases for EBV-associated SMT located in brain or spine. We identified 52 patients from the literature and performed a pooled analysis.

RESULTS

All patients in this cohort except one were immuno-suppressed from HIV, post-transplant therapy or because of CIS. Female predominance and a median age of 35 years was identified as was frequent multifocality. Therapeutic strategies varied but were mostly multidisciplinary with surgery.

CONCLUSION

Based on our results, EBV-associated SMT should be included in the differential diagnosis of intracranial lesions mimicking meningiomas in immuno-suppressed patients. Stereotactic radiosurgery can be offered as an alternate treatment option for suitable lesions. Long-term surveillance via MRI scanning is recommended for follow up.

Secondary Diffuse Large B-cell Lymphoma Mimicking Meningioma

Meningiomas are the most common benign intracranial tumors accounting for up to 30% of non-glial tumors of the central nervous system (CNS); on neuroimaging studies, they usually appear as a lobular, extra-axial mass with well-circumscribed margins mostly located in the parasagittal aspect of the cerebral convexity. On magnetic resonance imaging (MRI) of the brain, meningiomas are typically isointense to hypointense relative to grey matter in the T1-weighted sequence and isointense to slight hyperintense relative to grey matter on the T2-weighted sequence with avid homogeneous enhancement after contrast administration. A thin linear enhancement along the dura infiltrating away from the lesion, known as the dural tail sign, was once thought to be a pathognomonic feature of meningiomas, but this non-specific sign can also be seen in other meningioma-like lesions. Several benign and malignant pathologies may mimic some of the neuroimaging characteristics of meningiomas; among them dural metastases of lymphomas. When approaching a patient with suspected meningioma, close attention to the neuroimaging features may help distinguish them from meningioma-like lesions. Here we present the case of a woman with CNS involvement of non-Hodgkin lymphoma that presented with a dural mass resembling the neuroimaging characteristics of a meningioma. 

Multiple myeloma presenting as dural plasmacytoma

The finding of intracranial, extramedullary plasmacytoma is rare in multiple myeloma, especially with dural involvement. Meningioma remains the most common intracranial extra-axial mass. We report a case of a 39-year-old male who presented with intracranial, extra-axial mass found later to be dural plasmacytoma and additional multiple lesions on skeletal survey, leading to a diagnosis of multiple myeloma. The objective of this case is to increase awareness of the possibility of dural plasmacytoma as a differential diagnosis of meningioma and a harbinger of multiple myeloma. Magnetic resonance imaging plays a vital role in the detection of additional lesions in individuals while excluding multiple myeloma.

Dural and Leptomeningeal Spine Metastases of Breast Cancer

We present a case of a 57-year-old female diagnosed with invasive ductal breast cancer, which was treated and in remission for 12 years. In 2018 she presented a progressive dorsal back pain, which prevented her from performing basic tasks. An MR study was performed and revealed the presence of an extramedullary metastatic sleeve located in the thoracic intradural space. Concomitant multiple small nodular foci were adhering diffusely to the spinal cord, compatible with leptomeningeal metastatic disease. The occurrence of both forms of spread in the spine is uncommon, and its distinction on imaging is of particular importance taking into account the differences in treatment approach and prognosis.

Subdural haematoma mimics

A subdural haematoma (SDH) is a frequently encountered pathology seen on an emergency room computed tomography (CT) head scan. An extra-axial crescentic density along the convexity of the brain or within the interhemispheric fissure is generally thought to represent a SDH; however, SDH mimics are known to occur in nature, and can be broadly classified under the subcategories of normal anatomy, artefacts, tumour, inflammation, infection, ischaemia, trauma, and iatrogenic. Understanding the typical characteristics of a SDH, knowledge of normal anatomy, close inspection of the morphology of the subdural process, changes to the adjacent structures, and rigorous attention to clinical details may reveal subtle clues that distinguish a true SDH from a mimic. This is crucial in appropriately directing clinical management. This review amalgamates most of the rare subdural processes that have been reported to mimic SDH, and discusses the imaging and clinical features that help to differentiate between them. This topic is highly valuable for radiology trainees, general radiologists, and emergency room physicians, and may serve as a refresher for the practising neuroradiologist.

Rosai-Dorfman disease with spinal and multiple intracranial involvement: a case report and literature review

Rosai-Dorfman disease (RDD) is a condition of unknown etiology, and characterized by the proliferation of histiocytes. RDD most commonly affects lymph nodes, and central nervous system (CNS) involvement is rare. Here, we describe the case of a 43-year-old man who presented with an intradural tumour of the thoracic spine. The patient underwent a laminectomy for tumour resection and pathology results diagnosed the tumour as a RDD. Two years later, brain magnetic resonance imaging (MRI) revealed multiple intracranial dural-based lesions. Prednisolone treatment was initiated and led to resolution of the disease. We reviewed the literature to the investigate clinical characteristics, imaging features, diagnosis and treatment protocols pertaining to such cases.

Whole-tumor histogram analysis of apparent diffusion coefficient in differentiating intracranial solitary fibrous tumor/hemangiopericytoma from angiomatous meningioma

PURPOSE

To assess the role of histogram analysis of apparent diffusion coefficient (ADC) maps based on whole-tumor in differentiating intracranial solitary fibrous tumor/hemangiopericytoma (SFT/HPC) from angiomatous meningioma (AM).

MATERIALS AND METHODS

Pathologically confirmed intracranial SFT/HPC (n = 15) and AM (n = 20) were retrospectively collected and their clinical and conventional MRI features were analyzed. Diffusion-weighted (DW) images (b = 0 and 1000 s/mm²) were processed with the mono-exponential model. Regions of interest covering the whole tumor were drawn on all slices of the ADC maps to obtain histogram parameters, including mean ADC (ADCmean), median ADC (ADCmedian), maximum ADC (ADCmax), minimum ADC (ADCmin), skewness and kurtosis, as well as the 5th, 10th, 25th, 75th, 90th and 95th percentile ADC (ADC5, ADC10, ADC25, ADC75, ADC90 and ADC95). Differences of histogram parameters between SFT/HPC and AM were compared using Mann-Whitney U test. Receiver operating characteristic (ROC) curve was used to determine the diagnostic performance.

RESULTS

The ADCmin (P = 0.001) and ADC5 (P = 0.045) were significantly lower in SFT/HPCs than in AMs, while no significant difference was found in sex, age, conventional MRI features or any other histogram parameters between the two entities (P = 0.051-1.000). ADCmin showed the best diagnostic performance (area under curve [AUC], 0.86; sensitivity, 81.3%; specificity, 83.3%) in differentiating SFT/HPC from AM with optimal cutoff value being 569.00 × 10^-6  mm²/s, followed by ADC5 (AUC, 0.72; sensitivity, 68.8%; specificity, 75%) with optimal cutoff value being 781.97 × 10^-6  mm²/s.

CONCLUSION

SFT/HPC and AM share similar conventional MR appearances. Whole-tumor histogram analysis of ADC maps may be a useful tool for differential diagnosis, with ADCmin and ADC5 being potential parameters.

A Missed Differential in an Extra-Axial Lesion with Calvarial Involvement

Extra-axial central nervous system lesions can occasionally involve the overlying calvarium. The involvement may be due to longstanding pressure effects or secondary to the aggressive behaviour of the lesion. The spectrum of such dural-based lesions varies from infectious/inflammatory to neoplastic etiology. We present a dural-based lesion with the erosion of the overlying calvarium in a young lady. In view of the short history with heterogenous enhancement on magnetic resonance imaging and bony erosion, hemangiopericytoma or malignant meningioma was suspected. The histopathology, however, proved it to be an anaplastic (grade III) ependymoma. Extra-axial ependymomas though uncommon have been reported. However, these extra-axial ependymomas presenting with calvarial erosion are unknown. The bony erosion, as in the present case, may suggest an aggressive tumour behaviour. The reported extra-axial supratentorial ependymomas along with their salient radiological/operative features are shortly reviewed. Also, the differentials of extra-axial lesions with calvarial involvement are touched upon.