Cerebellopontine Angle Mass Research Articles

Atypical Teratoid Rhabdoid Tumor of the Brain in a Young Adult With Down Syndrome: Case Report and Literature Review.

Atypical teratoid/rhabdoid tumor (ATRT) is an aggressive, malignant embryonal tumor with dismal long-term survival despite aggressive multimodal therapy. While this tumor typically presents in infancy or early childhood, there are published case reports of adult-onset ATRT. Making prognostic conclusions or therapeutic decisions for this older patient population remains challenging due to the paucity of these reports. A 25-year-old female with Down syndrome presented with dysphagia and facial droop and was found to have an avidly enhancing, cerebellopontine angle mass. Histology demonstrated sheets of rhabdoid cells with loss of INI1 expression, pathognomonic for ATRT. Further sequencing detected a frameshift SMARCB1 mutation and methylation profiling matched with high confidence to the MYC subclass of ATRT. The patient was treated with subtotal surgical resection and focal proton beam irradiation, followed by chemotherapy on a modified regimen due to concern for heightened risk of treatment-related toxicity. On most recent follow-up 22 months from diagnosis, the patient remains without evidence of disease. This report represents the first known case of ATRT in a young adult patient with Down syndrome, offering unique mechanistic insight into the tumorigenesis of ATRT. Further studies are needed to define an appropriate risk-adapted and standardized therapeutic approach for this patient population.

NOT THE USUAL SUSPECTS: GLIOBLASTOMA OF THE CEREBELLOPONTINE ANGLE MASQUERADING AS A VESTIBULAR SCHWANNOMA

Introduction Most tumoral processes involving the cerebellopontine angle (CPA) are extraneuraxial and usually comprise of vestibular schwannomas and meningiomas, followed by less common lesions such as epidermoid cysts, metastases and arachnoid cysts. Glioblastomas located in the CPA are rarely diagnosed. Uncommonly, intraneuraxial tumors in the CPA may grow in an exophytic manner compressing the surrounding cranial nerves, resembling the clinical picture of a more common extraneuraxial tumour. Clinical Case A 47 year old male presented to our department accusing gait imbalance, vertigo, vomiting and nausea, symptoms that started 2 months prior to admission. Upon neurological examination, the patient additionally presented right facial paresis and hypoesthesia, right sided hypoacusis, hypogeusia and diplopia. A contrast enhanced cerebral MRI revealed a right cerebellopontine angle mass with inhomogenous contrast enhancement, relatively well delineated, exerting mass effect on the cerebellum and pons with reduced perilesional edema but with involvement of the internal acoustic meatus. The indication for surgical removal of the tumour was made. The patient was placed in sitting position and a right retrosigmoid approach was performed using the operating microscope. Upon retraction of the cerebellar hemisphere, a greyish, highly vascularized and soft lesion was seen, exhibiting a spread growth, engulfing the V, VII and VIII nerves, without infiltrating them, resembling anything but a schwannoma. A frozen section of the tumour revealed a surprising result: high grade glioma. The surgical excision continued in a piece-meal fashion, using the ultrasonic aspirator with preservation of the cranial nerves until an almost complete removal was achieved. The immediate postop evolution of the patient was favourable. Nevertheless, the final histopathological diagnosis confirmed a grade IV glioblastoma. Oncological treatmend followed, but the tumour relapsed in 2 months after surgery, the control MRI revealing a multilocular tumoral dissemination in the cerebellum and brainstem which was surgically unsalvageable. Conclusion Glioblastoma of the CPA, manifesting both imagistically and clinically as a vestibular schwannoma is a rare entity but nevertheless extant, that dramatically changes the prognosis and postop evolution of a patient. Physicians involved in the diagnosis and treatment of such tumours must always be suspicious of the usual suspects in the CPA.

Gustatory Function in Patients With Cerebellopontine Angle Masses.

To investigate the impact of cerebellopontine angle (CPA) masses on subjective and measured taste function. Retrospective cross-sectional study. Tertiary referral center. Consecutive adult patients with untreated CPA masses. Gustatory function was psychophysically measured with Taste Strips (range, 0-16) on both sides of the tongue. Subjective taste complaints were assessed using a questionnaire. Half-sided taste impairment (hemi-ageusia) was defined as side-to-side asymmetry ≥4 points with <9 points on the side of the CPA mass. We used the Koos classification for vestibular schwannomas (VS) and, in the case of facial nerve palsy, the House-Brackmann grading system. We included 135 patients (mean [standard deviation (SD)] age, 55.3 ± 14.1 yr; 62 males). The most common CPA mass was VS (77%). Overall, the measured taste function was lower on the affected compared with the healthy side of the tongue (mean score, 9.8 ± 3.3 versus 11 ± 2.9; p < 0.0001). Looking for clinically relevant one-sided taste impairment revealed 18 (13.3%) patients with hemi-ageusia, but only 4 (30.8%) of those subjectively complained of taste dysfunction. Regarding VS, Koos IV masses presented the lowest score on the affected side (mean score, 7.5 ± 3.7). Six patients presented with facial palsy. Having facial palsy did not result in a lower Taste Strips score (p = 0.23). Before any CPA mass treatment, a measurable ipsilateral decrease in gustatory function is present in many patients. Most patients do not notice this preexisting taste impairment. From a medicolegal standpoint, this warrants consideration. To avoid postoperative claims regarding taste function, a preoperative assessment may be considered.

ICU Management of Post-Craniotomy Patients with Schwannoma Vestibular Tumor Removal

Background: Vestibular schwannoma (VS) is a relatively common tumor that arises from the vestibulocochlear nerve (CN VIII) and represents 80% of cerebellopontine angle (CPA) masses. CPA tumors are mostly benign, slow growing with low malignant potential (~1%). VS have rarely been reported, and there is a lack of in-depth discussion on the experience of management of massive acoustic neuromas in ICU. It represents the case in which the patient presented with obstructive hydrocephalus and progressive neurological deficits. The purpose of this case report is to understand the management of post-operative patients with VS with several comorbidities in the ICU.Case: We present a 53 years old woman with a giant VS and obstructive hydrocephalus. An imaging findings revealed a brain tumor in the CPA region and obstructive hydrocephalus. Consequently, she relieved her hydrocephalus with a ventriculoperitoneal shunt (VP shunt). After 1.5 years, her mental condition deteriorated, and her left limb muscle strength gradually decreased. Under a joint consultation with Department of Neurosurgery and Anesthesiology, she underwent tumor removal. Upon discharge, the previously observed neurological deficits, which were reversible had been successfully resolved. The neuroimaging confirmed the complete tumor removal, while the neuropathologic examination revealed a VS.Discussion: If untreated, an acoustic neuroma can grow large enough to cause pressure on the brain stem. The tumor can block the flow of cerebrospinal fluid (CSF) between the brain and the spinal cord, causing a buildup of the fluid in the brain. Because the skull is a closed structure, excess fluid in the brain (hydrocephalus) can press against the brain, causing unsteady movement and lack of coordination (ataxia), headaches and confusion. Patients with brainstem compression had significantly longer mean LOS than patients without. Also, the dissection of the facial nerve from the tumor in order to preserve it can sometimes cause swelling, which can result in weakness or paralysis (complete or partial loss of muscle function). This is usually temporary but can take weeks to months to recover. After the operation, the patient was treated in the ICU, a ventilator was installed,insulin was given to regulate blood sugar and anti-hypertension medication for maintaining blood pressure. During treatment in the ICU, adequate fluids and nutrition are provided. Monitoring is carried out on cardiovascular function, hemodynamics and respiration by monitoring blood pressure, electrocardiogram (ECG), oxygen saturation. The patient was moved to high care unit (HCU) after being treated for 3 days in the ICU.Conclusion: Postoperative therapy is more focused on supportive therapy, including maintaining the airway, regulating blood sugar, blood pressure and providing mechanical ventilation to maintain adequate oxygenation.

ATRT-08. ATYPICAL TERATOID RHABDOID TUMOR IN AN ADULT PATIENT WITH DOWN SYNDROME

Abstract BACKGROUND Atypical teratoid/rhabdoid tumor (ATRT) is a malignant, highly aggressive embryonal tumor of the central nervous system. Long-term survival remains dismal despite aggressive multimodal therapy, including a maximal safe surgical resection and intensive systemic chemotherapy +/- radiation therapy. While these tumors typically present in infancy or early childhood, there are scattered case reports of adult-onset ATRT. Making prognostic conclusions or therapeutic decisions for this older patient population remains challenging due to the paucity of these reports. CASE REPORT A 25-year-old female with Down syndrome presented with nausea, vomiting, dysphagia, and facial droop and was found to have an avidly enhancing, left cerebellopontine angle mass. There was initial clinical suspicion for leukemic chloroma given the patient’s Down syndrome status and known association with higher rates of hematologic malignancy concurrent with a dramatic scarcity of solid tumors in the Down syndrome population. However, histology demonstrated sheets of high-grade rhabdoid cells with loss of INI1 expression, pathognomonic for ATRT. Further sequencing defined a frameshift mutation in SMARCB1 (p.C298), and methylation profiling matched with high confidence to the MYC subclass of ATRT. The patient was treated with subtotal surgical resection and focal proton radiation, followed by chemotherapy on a modified regimen based on the Children’s Oncology Group protocol, ACNS0333. Systemic methotrexate and all consolidative high-dose chemotherapy with stem cell rescue were omitted due to concern for heightened risk of treatment-related toxicity. The patient remains alive and clinically asymptomatic 19 months from diagnosis. CONCLUSION This report represents the first known case of ATRT in an adult patient with Down syndrome, offering unique mechanistic insight into the tumorigenesis of ATRT. Adult ATRT is a rare entity without standardized treatment or established prognostic understanding. Further studies are needed to define an appropriate risk-adapted therapeutic approach for this patient population.

Concurrent Isolated Hypoglossal Nerve Palsy Induced by Jugular Vein Thrombosis, Cervical Plexus Masses, and Vestibular Schwannoma: A Complex Case Report Highlighting Anatomical Pathways and Clinical Challenges

Background: Hypoglossal nerve palsy is typically observed alongside other cranial nerve impairments, with isolated cases being infrequent and posing diagnostic complexities. Originating intracranially, the nerve traverses the skull and neck, governing tongue motility. Lesions are classified as supranuclear, nuclear, or infranuclear, engendering tongue deviation towards the affected side. Due to its proximity to crucial structures, hypoglossal nerve palsy often coincides with supplementary symptoms. Etiologies encompass skull base metastases, carotid artery pathologies, and trauma. This study explores less conventional triggers such as hypoglossal nerve palsy following thyroidectomy, jugular vein thrombosis, cervical plexus masses, and Vestibular Schwannoma. Case Description: A 38-year-old female presented to the Neurology outpatient clinic with leftward tongue deviation and left-sided neck and shoulder pain accompanied by stiffness that had begun several months prior. In addition to the tongue deviation, she reported minor dysphagia, blurry vision, and intermittent numbness on the left side of her scalp. MRI and duplex ultrasound verified the presence of left internal jugular vein (IJV) thrombosis. The patient was initially prescribed Eliquis and acetazolamide, with slight improvements in symptoms, though medication use ceased due to side effects. During a subsequent follow-up visit, persistent tongue deviation and worsening left shoulder pain prompted additional cervical imaging. A new cervical spine MRI revealed a 15x14 mm nodular dural enhancement with a paraspinal soft tissue mass at the C2 level. Concurrently, multiple cranial nerve palsies were detected during the physical examination. Unfortunately, the patient was subsequently diagnosed with breast cancer. To rule out brain metastases related to her breast cancer, an additional brain MRI was performed, revealing a newly formed 2.3x1.6x1.2 cm left cerebellopontine angle mass adjacent to the internal auditory canal (IAC), suggestive of a vestibular schwannoma but without evidence of metastatic disease. The patient's care involved a multidisciplinary team, including hematologist-oncologists, neurosurgeons, and neurologists. Conclusion: This case report highlights the less common causes of hypoglossal nerve palsy, such as jugular vein thrombosis, cervical plexus masses, and Vestibular Schwannoma. The persistence of the patient's palsy is attributed to the cumulative impact of these anatomical factors on the hypoglossal nerve. This underscores the diagnostic challenges posed by isolated hypoglossal nerve palsy and emphasizes the importance of comprehensive clinical evaluation and imaging for accurate diagnosis.

Capability of constructive interference in steady state sequence versus postcontrast T1-weighted imaging in cerebellopontine angle and internal auditory canal masses

Background: The tumor size is one of the main factors in the treatment of cerebellopontine angle (CPA) tumors, and magnetic resonance imaging (MRI) with gadolinium-based contrast agent (GBCA) provides the best evaluation. However, administration of the gadolinium is time consuming and increasing in cost. There is a risk of nephrogenic systemic fibrosis in patients with renal failure and liver or renal transplantation. Objective: The purpose of this study was to assess the capability of constructive interference in steady state (CISS) sequence in measuring the tumor size of the CPA and internal auditory canal (IAC) masses compared to postcontrast T1-weighted images (T1-WI). Materials and Methods: The 118 MR studies with both CISS sequence and postcontrast T1-WI of 45 patients with CPA and IAC masses were retrospectively reviewed. Results: There was no significant difference between CISS and postcontrast T1-WI in measuring size in transverse diameter of the masses (p = 0.051-0.06). The longitudinal diameter measurement revealed a significant difference (p &lt; 0.001) and the measured size on postcontrast T1-WI was slightly larger than the CISS image. The difference in median measurement between two sequences was less than 0.9 mm. and Bland-Altman plots revealed that differences between the two sequences in longitudinal and transverse diameters of the masses were within the limits of agreement. Interobserver agreement showed excellent correlation (r = 0.994-0.999, p &lt; 0.001 by Pearson's product-moment correlation). Conclusions: The CISS sequence may be sufficient for assessing the size of CPA and IAC masses, which can be used interchangeably with postcontrast T1-weighted image as a contrast-free option, especially in follow-up studies and vulnerable settings of gadolinium administration.

Vestibular schwannoma: Ice cream cone sign

Vestibular schwannoms is a benign extra-axial tumor the most frequent cerebellopontine angle masses. It can interfere with the face nerves, causing facial numbness and paralysis. (MRI) is the most specific and first intention examination to make the diagnosis.

Vestibular schwannoma: Ice cream cone sign

Vestibular schwannoms is a benign extra-axial tumor the most frequent cerebellopontine angle masses. It can interfere with the face nerves, causing facial numbness and paralysis. (MRI) is the most specific and first intention examination to make the diagnosis.

Magnetic Resonance Diffusion, Spectroscopy and Susceptibility Imaging in Evaluation of Cerebellopontine Angle Masses

Magnetic Resonance Diffusion, Spectroscopy and Susceptibility Imaging in Evaluation of Cerebellopontine Angle Masses

HISTOPATHOLOGICAL APPROACH TO THE DIAGNOSIS OF BENIGN PERIPHERAL NERVE SHEATH TUMORS AT UNCOMMON LOCATION

Peripheral nerve sheath tumors are relatively common lesions that exhibit a wide morphological and biological spectrum. In the presence of classical morphological and immunohistochemical features, the histological diagnosis is usually straightforward, but they may represent diagnostic challenges. Schwannoma is a slow growing encapsulated tumor of neuroectodermal derivation that originates from the Schwann cells of the neural sheath. Most commonly presents as cerebellopontine angle mass but extracranial sites are known and needs to be considered in the differential diagnosis. Intraparotid and penile schwannomas are extremely rare. Their diagnosis could be missed on cytology due to cystic changes. Isolated plexiform neurofibroma of the tongue is again a rare tumor. Plexiform pattern recognition is important for the pathologist as these varients might show malignant transformation. Overall Fine needle aspiration cytology though inconclusive at times, help a lot initially to delineate between benign Vs malignant lesions. Moreover its minimally invasive so can be performed easily at the uncommon locations. Histopathology remains the gold standard. Clinicopathological and imaging correlation is must for definite diagnosis and treatment.

Labyrinthitis With Negative MRI As a Precursor to Rapidly Developing Primary CNS Lymphoma of the Cerebellopontine Angle.

Few case reports have described primary central nervous system lymphoma (PCNSL) presenting as a cerebellopontine angle (CPA) lesion in HIV-positive patients. We describe a rare presentation of rapidly progressing PCNSL of the CPA/internal auditory canal (IAC) as labyrinthitis with initial negative MRI in an HIV-positive patient. A 58-year-old male with well-controlled HIV presented with sudden left sensorineural hearing loss, tinnitus, and imbalance. Vestibular testing suggested an uncompensated left peripheral vestibular weakness. MRI demonstrated facial and cochleovestibular nerve enhancement within the CPA and IAC. The presumptive diagnosis of labyrinthitis was made. Two months later, he presented to his infectious disease provider with left facial weakness and disequilibrium and was treated for presumed Bell's palsy. One month later, he presented with left corneal reflex dysfunction, decreased visual acuity, diplopia, and worsening ataxia. Repeat MRI demonstrated a new 3.6 cm lesion of the left CPA/IAC with vasogenic edema. Despite location, the mass lacked the brainstem compression characteristic of other extra-axial CPA masses such as vestibular schwannoma. Flow cytometry and cytology from cerebrospinal fluid was consistent with primary central nervous system large B-cell lymphoma. We present a unique case of rapidly progressing PCNSL of the CPA/IAC in an HIV-positive patient, presenting initially as labyrinthitis with negative MRI followed by development of multiple cranial neuropathies and 3-month repeat MRI demonstrating a large CPA mass. In HIV-positive patients with a similar initial presentation, PCNSL should considered early in the diagnostic evaluation with close clinical monitoring and a low threshold for repeat imaging.

Primary intracranial extraosseous Ewing's sarcoma of the skull base in an elderly adult: illustrative case.

BACKGROUNDPrimary extraosseous intracranial Ewing’s sarcoma, also known as a peripheral primitive neuroectodermal tumor or “small round blue cell tumor,” is an extremely rare entity with limited representation in the literature beyond the pediatric population.OBSERVATIONSA 67-year-old male suffering occipital headache, nausea, and gait disturbance was found to have a large, avidly contrast-enhancing cerebellopontine angle mass extending into the cervical spinal canal with associated mass effect on medulla, cerebellum, fourth ventricle, and cervical spinal cord. This mass was not present on the imaging from 8 years prior. He underwent surgical debulking and pathology results demonstrated a malignant small round cell tumor showing diffuse immunopositivity for cytokeratins, CD99 and NKX2.2 with EWRS1-FLI1 rearrangement in 84% of the nuclei confirmatory of Ewing’s sarcoma. After 14 cycles of chemotherapy and 6 weeks of radiotherapy, 22 months after discovery, the patient remains in clinical and radiographic remission with complete return to his baseline functioning.LESSONSPrimary skull base extraosseous Ewing’s sarcoma should be considered in the differential diagnosis even in the elderly population when imaging studies demonstrate aggressive tumor growth patterns. Tumor debulking to establish a diagnosis followed by adjuvant chemoradiation therapy can result in clinical improvement with remission.

Tear matrix metalloproteinase-9 levels may help to follow a ocular surface injury in lagophthalmic eyes.

The preocular tear film is critically important for maintaining healthy ocular surface. In lagophthalmos, increased evaporation and tear film instability can occur. The level of tear matrix metalloproteinase 9 (MMP-9) is considered as a possible marker of ocular surface damage and inflammation. The aim of this study was to evaluate the possible usefulness of measuring tear film levels of MMP-9 in patients with lagophthalmos. Sixteen adult patients with unilateral lagophthalmos due to cerebellopontine angle mass surgery were included. Basic clinical examination including tear film osmolarity, degree of lagophthalmos, ocular surface sensitivity testing, corneal fluorescein staining, and tear break-up time (TBUT) were performed. Furthermore, tear MMP-9 quantification was performed and the values from lagophthalmic and contralateral healthy eye were compared. Possible correlations between tear MMP-9 levels and other parameters were analyzed. The Oxford score was higher in lagophthalmic eyes in comparison to healthy eyes. TBUT and corneal sensitivity were lower in lagophthalmic eyes. There was no difference in osmolarity between the two groups. Tear MMP-9 values were higher in lagophthalmic eyes. A higher MMP-9 value was associated with an increase in ocular surface fluorescein staining and a decrease of TBUT in lagophthalmic eyes. Tear MMP-9 may be used for monitoring ocular surface damage, contribute to early detection of inflammation progression and facilitate treatment adjustments.

Mass phenomena from a cerebellopontine angle arachnoid cyst: case report

Introduction. Arachnoid cysts are benign lesions comprising about 1 % of all intracranial space occupying lesions. The majority are asymptomatic, while surgical intervention, consisting of fenestration, is suggested in the presence of mass phenomena.The aim of the study – to present the case of a patient with arachnoid cysts in the cerebellopontine angle and its treatment.Materials and methods. A 53‑years old female patient was referred to our Department of Neurosurgery for the surgical management of a cerebellopontine angle mass. The patient reported tingling sensation and causalgia of her left hemiface, dysarthria, hoarseness, difficulty swallowing solid food and liquids, tinnitus and pain distributed along the ophthalmic branch of the trigeminal nerve.Results. The patient was subjected to retrosigmoid craniotomy with fenestration of the cyst and concurrent placement of a Torkildsen shunt. No complete resection of the capsule of the cyst was attempted, due to its tight adhesions to the adjacent structures. Postoperatively, there was an improvement in the dysarthria and swallowing of the patient.Conclusions. Cerebellopontine angle cystic lesions while histologically benign, may become clinically apparent due to compression of adjacent structures. Simple fenestration of the cyst may be sufficient for the remission of symptoms.

Extra-axial adult cerebellopontine angle medulloblastoma

A purely extra-axial position of medulloblastoma in adults at cerebellopontine (CP) angle is extremely rare. To the best of our knowledge, only ten cases have been reported till date. The authors report a case of extra-axial medulloblastoma in a 30-year-old female located at right CP angle. It was surgically treated with a provisional diagnosis of meningioma. Histopathological diagnosis of desmoplastic/nodular medulloblastoma was made with the routine hematoxylin eosin (HE) stain and immunohistochemical markers. This case report highlights the fact that, although extremely rare, the possibility of an extra-axial CP angle mass being a medulloblastoma still needs to be considered in the differential diagnoses, even in adults.

Utility of Microhemorrhage as a Diagnostic Tool in Distinguishing Vestibular Schwannomas from other Cerebellopontine Angle (CPA) Tumors.

Although a majority of tumors in the Cerebellopontine Angle (CPA) are vestibular schwannomas (VS), other masses can also be seen in the region and differentiation of various CPA tumors, particularly meningiomas can be difficult on imaging alone. Treatment options may vary based on specific pathology of the CPA tumor. In this study, the presence of microhemorrhage (MH) and other imaging features such as size of lesion, cystic features and pattern of IAC extension, were evaluated as a tool in distinguishing VS from other CPA masses. A review of CPA masses in the last 11years at our institution was performed. All the pathology proven tumors with at least 1 pre-operative MRI were considered for analysis. A T2* GRE or SWI sequence was used to assess presence of MH within the lesion. Pattern of IAC extension ('centric' versus 'eccentric') of tumor was also evaluated. A total of 147 patients were reviewed out of which 102 patients (with T2* GRE or SWI) were included for analysis of MH. 57 patients (56%) had VS as the final histopathological diagnosis and 45 patients (44%) had other types of tumor. A sensitivity of 82% and a specificity of 98% was noted for the presence of MH favoring the diagnosis of VS from other tumors (p < 0.001). All meningiomas with IAC extension (25/31) showed an 'eccentric' pattern of extension into the canal. Visualization of MH and pattern of IAC extension is useful in the differentiation of schwannomas from other CPA masses, particularly meningiomas.

RARE-20. MALIGNANT PERIPHERAL NERVE SHEATH TUMOR OF A CRANIAL NERVE IN AN INFANT WITH NEUROCUTANEOUS MELANOSIS

At one month of age, a female presented with a giant congenital nevus along lower back and thighs and hydrocephalus. A ventriculoperitoneal shunt was placed. An MRI was done at six months, initially reported as normal. At eleven months of age, five months after original MRI, patient presented with dysconjugate gaze and lethargy. MRI showed new 3.8 x 3.7 x 3.4 cm right cerebellopontine angle mass extending into Meckel’s cave and foramen ovale along with leptomeningeal disease extending from the mass along the entire length of the spinal cord. Retrospective review of prior MRI revealed subtle leptomeningeal enhancement concerning for neurocutaneous melanosis (NCM). Given the leptomeningeal disease, family elected for open biopsy and debulking of lesion instead of aggressive resection. Histologically, the mass showed hypercellular spindle cell neoplasm with mitotic activity and necrosis mixed with remnants of normal cranial nerve. GFAP was negative, excluding a glioma. HMB-45, MITF, panmelanoma, and Melan-A were negative, excluding melanoma. A negative myogenin stain ruled out ectomesenchymoma. S-100 protein and SOX-10 positivity with variable loss of staining for trimethylation of histone H3 K27 were indicative of malignant peripheral nerve sheath tumor (MPNST). Given the course of the mass, trigeminal nerve MPNST was presumed. Given the poor prognosis of intracranial MPNST and NCM, family elected to forgo treatment and was discharged with hospice. She died 25 days after surgery. Cranial nerve MPNST is rare. MPNST in patients with NCM has not previously been reported to our knowledge.

Absence of contrast enhancement in a petroclival meningioma: Case report and systematic literature review

Background: Meningioma is one of the most common intracranial tumors with well-established radiologic features such as contrast enhancement, dural tail, and hyperostosis on computed tomography and magnetic resonance imaging. Contrast enhancement is usually homogeneous or heterogeneous based on tumor vascularity and underlying histopathology. Even in this context, faint or nonenhancing meningioma is exceedingly rare.Case Description: A 57-year-old male presented with progressive right hearing loss, disequilibrium, occasional difficulty swallowing, and facial numbness. Imaging demonstrated an extensive hypodense, nonenhancing right cerebellopontine angle mass extending from the interpeduncular, and ambient cisterns to the foramen magnum. The pathological analysis demonstrated a microcystic meningioma WHO Grade I. There are few reported case reports or series of minimal or nonenhancing meningiomas, and a systematic review was performed for these cases. Seven peer-reviewed articles with 14 verifiable cases were identified and reviewed for radiologic features, tumor location, and tumor classification. The majority of minimal or nonenhancing meningiomas were microcystic, and most of them located at the convexity. This is the second case reported of a nonenhancing meningioma at the cerebellopontine angle and petroclival regionConclusion: Meningioma should be considered a differential diagnosis for nonenhancing lesion at the cerebellopontine and petroclival regions.

Stuck in the Middle: Nervus Intermedius‐Related Neuropathologic Imaging Spectrum

The nervus intermedius is a complex nerve that traverses the cerebellopontine angle and is associated with a wide range of pathologies for which imaging plays a crucial diagnostic role. Cerebellopontine angle masses or neurovascular compression may directly involve the nervus intermedius. Alternatively, pathologies that involve branches of the nervus intermedius may present with symptoms referable to the nervus intermedius, including sinonasal tumors, perineural tumor spread, or viral reactivation such as in Ramsay Hunt syndrome. Overlapping innervation with branches of the trigeminal, glossopharyngeal, and vagus nerves can confound diagnosis and/or lead to mislocalization, which may result in delayed diagnosis or inappropriate therapy. This review article provides an in-depth overview of nervus intermedius anatomy and physiology, and the wide spectrum of pathologies that can involve the nervus intermedius or its branches, with an emphasis on clinical relevance.Learning Objective: To understand the normal anatomy and physiology of the nervus intermedius as well as the clinical relevance and imaging findings of the neuropathologic spectrum of disease referable to the nervus intermedius and its branches: the greater superficial petrosal nerve, the chorda tympani, and the sensory auricular branch.