Diagnosis and Outcome of Biopsies of Indeterminate Lesions of the Cavernous Sinus and Meckel's Cave: A Retrospective Case Series in 85 Patients

A case series of percutaneous transforamen ovale biopsies in cavernous sinus lesions

BACKGROUND

The majority of cavernous sinus lesions are meningiomas, for which treatment (fractioned radiotherapy or radiosurgery), if indicated, is usually initiated upon image-based diagnosis. However, this region can be affected by a wide variety of pathological processes and the risk of misdiagnosis exists. As pathological diagnosis can be obtained by biopsy through the foramen ovale in selected cases, we asked the question as to whether systematically performing this procedure before treatment would provide additional, relevant diagnostic information.

METHODS

All the cases referred to our department between January 2008 and December 2019 for cavernous sinus lesions that were considered for treatment and anatomically suitable for transforamen ovale biopsy were included. Outcomes and subsequent treatment or follow-up data were collected.

RESULTS

Thirty-five patients were included. Twenty-six were highly suspected to have meningioma or schwannoma at imaging, among whom biopsy allowed diagnosis confirmation in 17 cases (65%). For the nine patients for whom biopsy was indicated upon suspected malignancy or inflammatory disease on imaging, biopsy revealed three meningiomas and one lymphoma and was not contributory in five cases (56%), three of which underwent open surgery. Three patients (8.5%) had persistent neuralgia at the last follow-up.

CONCLUSIONS

When cavernous sinus meningioma or schwannoma is highly suspected upon predefined imaging criteria by an experienced neuroradiologist, invasive exploration before treatment does not seem to be indicated. Otherwise, transforamen ovale biopsy might be consider in selected cases as a minimally invasive option to obtain pathological analysis.

Flatness of the Meckel cave may cause primary trigeminal neuralgia: a radiomics-based study

Background

Neurovascular contact (NVC) is the main cause of primary trigeminal neuralgia (PTN); however, cases of PTN without NVC are still observed. In this study, the Meckel cave (MC) morphology in PTN were analyzed by radiomics and compared to healthy controls (HCs) to explore the cause of PTN.

Methods

We studied the 3.0T MRI data of 115 patients with PTN and 46 HCs. Bilateral MC was modeled using the 3D Slicer software, and the morphological characteristics of MC were analyzed using the radiomics method.

Results

The right side incidence rate in the PTN group was higher than the left side incidence. By analyzing the flatness feature of MC, we observed that the affected side of the PTN was lower than that of the unaffected side, the right MC of the PTN and HC was lower than that of the left MC, the MC of the affected side of the left and right PTN without bilateral NVC was lower than that of the unaffected side.

Conclusions

By providing a method to analyze the morphology of the MC, we found that there is an asymmetry in the morphology of bilateral MC in the PTN and HC groups. It can be inferred that the flatness of the MC may be a cause of PTN.

Access to Meckel's cave for biopsies of indeterminate lesions: a systematic review

Accessing Meckel's cave (MC) is surgically challenging. Open approaches are complex and often correlated with high morbidity. Endoscopic approaches emerged in the last decade as feasible alternatives to open approaches, especially for sampling indeterminate lesions. This article first analyses available routes to approach Meckel's cave and presents furthermore an illustrative case. We conducted a systematic review and reported according to the guidelines for preferred reporting items for systematic reviews and meta-analyses (PRISMA). Various surgical approaches identified through the search are evaluated and discussed in detail. Additionally, we report on a case of woman with a lesion in MC, which was accessed through an endoscopic transpterygoid approach subsequently diagnosed as a diffuse large B cell lymphoma. Our search delivered 75 articles that included case reports (n = 21), cadaveric studies (n = 32), clinical articles (n = 16), review of the literatures (n = 3), as well as technical notes (n = 2) and a radiological manuscript (n = 1). Open routes included lateral approaches with many variations, mainly intra- and extradural pterional approaches and anterior petrosal, as well as a retrosigmoid intradural suprameatal and a lateral transorbital approach. Endoscopically, MC was reached via approaches that included transpterygoid, transorbital or infraorbital fissure routes. Percutaneous approaches, e.g. through the foramen ovale, were also described. Multiple surgical approaches to MC are currently available. Their different characteristics as well as individual patient factors, such as clinical history and the localization of the disease, have to be considered when choosing a surgical corridor. Studies included in this review highlight the endonasal endoscopic transpterygoidal technique as an excellent corridor for biopsies in the ventral MC.

Renal Cell Carcinoma with Primary Presentation via Metastasis to the Trigeminal Ganglion

BACKGROUND

Renal cell carcinoma (RCC) accounts for ∼8% of all brain metastatic disease; however, spread to the cranial nerves and their ganglia is uncommon. To the best of our knowledge, we report the first case of RCC metastatic to Meckel's cave, which was diagnosed secondary to new trigeminal sensory loss.

METHODS

A 45-year-old man had presented with acute-onset right V3 numbness. Magnetic resonance imaging demonstrated contrast enhancement of the ipsilateral V3, extending from its root at the Gasserian ganglion to the foramen ovale.

RESULTS

He elected for observation, and his symptoms resolved over several weeks. At the scheduled, routine 3-month follow-up examination, he reported symptomatic relapse with new concomitant hyperesthetic/neuropathic pain. Magnetic resonance imaging demonstrated interval enlargement of the enhancing lesion in an atypical pattern, potentially consistent with trigeminal schwannoma versus meningioma, and operative resection was recommended.

CONCLUSION

We have reported a case of RCC presenting with numbness via metastatic spread to Meckel's cave. Although uncommon, metastasis is an important diagnostic consideration for enhancing cranial nerve lesions. Our case has demonstrated that, although a history of malignancy, multiple lesions, or systemic/constitutional symptoms are typical, rare cases can demonstrate isolated central nervous system findings. Thus, short-term radiographic surveillance is indicated if the diagnosis of an intracranial or cranial nerve mass lesion is equivocal.

Imaging-Ambiguous Lesions of Meckel's Cave-Utility of Endoscopic Endonasal Transpterygoid Biopsy

INTRODUCTION

Meckel's cave is a dural-lined cavity in the middle fossa skull base in which lies the Gasserian ganglion, a potential site for tumors and inflammatory lesions. A variety of lesions can be predominantly isolated to Meckel's cave, including extension from head and neck cancers, other malignant tumors, as well as benign lesions. Clinical presentation and imaging findings are often insufficient to establish a diagnosis. Hence, histologic confirmation is required to determine the appropriate treatment strategy. Several surgical approaches have been used to reach this deep-seated area, often with significant morbidity and prolonged recovery. Given advancements in endoscopy and greater facility with the technique, the endoscopic endonasal approach has been used increasingly to reach lesions in the region.

METHODS

A single-institution, retrospective chart review over a 10-year period was performed to identify and describe patients with pathologically differing but imaging-similar lesions with their epicenter in Meckel's cave.

RESULTS

Of a total of 21 cases of lesions in Meckel's cave approached by an endoscopic endonasal transpterygoid approach, we present 6 patients with imaging-ambiguous lesions involving Meckel's cave that were biopsied via the extended endoscopic endonasal approach. Among this diverse group, pathology included B-cell lymphoma, squamous cell carcinoma, adenocarcinoma, malignant schwannoma, benign schwannoma, and neurosarcoidosis.

CONCLUSIONS

We explore not only the relevance of this approach in the armamentarium of the modern skull-base surgeon but also its limitations and conclude that the endoscopic endonasal approach provides a safe and relatively direct, minimally invasive corridor to many lesions of Meckel's cave.

Symptomatic Meckel's Cave Metastasis from Castration-resistant Prostate Cancer Treated with Gamma Knife Radiosurgery

Prostate cancer commonly spreads to the axial and appendicular skeleton, but metastases to the brain parenchyma or skull base are uncommon. In the cases that this happens, the symptoms are usually associated with disease involving the orbit. Metastasis to the Meckel’s cave causing trigeminal nerve palsy is an exceedingly rare entity. We are presenting a case of this in a man with metastatic castration-resistant prostate cancer. Metastatic prostate cancer to the Meckel's cave is extremely uncommon, and there is no standard of care. Radiation therapy, especially radiosurgery, is increasingly recognized as an excellent alternative to surgery for lesions in the Meckel’s cave and intracranial/skull base prostate cancer metastases. Gamma Knife radiosurgery (Elekta, Stockholm, Sweden), in particular, has been reported to achieve local control close to 90% for calvarial and skull base metastases with few side effects and requires only one treatment. Our patient’s 1.4 x 1.0 x 1.3 cm metastatic prostate cancer lesion in the Meckel's cave was treated with Gamma Knife to 22 Gy with good treatment response including rapid improvement in his symptoms and no side effects. We review the scarce literature documenting cases of prostate cancer metastatic to the brain or skull base and the only two other documented cases of prostate cancer metastasis the Meckel’s cave neither of which was treated with radiotherapy.