326 lines
33 KiB
Markdown
326 lines
33 KiB
Markdown
---
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title: "Cystic CPA Mass"
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docid: "6c60db6d-8093-4df5-8cbb-c6f6570ae167"
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authors:
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- key: "07a2c087-6202-49e7-870b-7aa162d18f06"
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value: "Bronwyn E. Hamilton, MD"
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breadcrumbs:
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-
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name: "Head and Neck"
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slug: "head-and-neck"
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treeNodeId: "ed24ed8c-5d57-4629-879b-447b82d2973d"
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-
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name: "Differential Diagnosis"
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slug: "differential-diagnosis"
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treeNodeId: "40d68862-8975-4dde-ac2b-ebc43ab0fb5c"
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-
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name: "CPA-IAC and Posterior Fossa"
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slug: "cpa-iac-and-posterior-fossa"
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treeNodeId: "c590eedb-4a3b-4158-a04f-ad880564c992"
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-
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name: "Generic Imaging Patterns"
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slug: "generic-imaging-patterns"
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treeNodeId: "ba996846-af9d-4714-b15b-84315b9ad282"
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-
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name: "Cystic CPA Mass"
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slug: "cystic-cpa-mass"
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treeNodeId: null
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category: "Head and Neck"
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cmeTopicId: "75974523-991b-4e4d-90c7-5a70d21f2598"
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documentVersionId: "dd13cf85-d7fc-40b3-b753-b3231a135c6b"
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imageCount: 23
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lastUpdated: "02/09/24"
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pageDescription: "Cystic CPA Mass"
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pageKeywords: "Head and Neck, Differential Diagnosis, CPA-IAC and Posterior Fossa, Generic Imaging Patterns, Cystic CPA Mass"
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pageTitle: "Cystic CPA Mass | STATdx"
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enhancedTitle: "Cystic CPA Mass"
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type: "DDX"
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references: true
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breadcrumbs:
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- "Head and Neck"
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- "Differential Diagnosis"
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- "CPA-IAC and Posterior Fossa"
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- "Generic Imaging Patterns"
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- "Cystic CPA Mass"
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---
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# ESSENTIAL INFORMATION
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- ## Key Differential Diagnosis Issues
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- This differential diagnosis is constructed around lesions of cerebellopontine angle (CPA) that may have "cystic" imaging features
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- Typically cystic lesions: Epidermoid, arachnoid, & neurenteric cysts; neurocysticercosis & large endolymphatic sac anomaly
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- Many solid CPA tumors may have either intramural cysts, necrosis, or extramural cysts as typical or variant MR imaging manifestation
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- Schwannoma: Vestibular, facial nerve, trigeminal, or jugular foramen schwannoma with intramural or extramural cysts can all be found in CPA area
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- Hemangioblastoma: Cerebellar cystic & solid tumor that may project into CPA cistern
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- Endolymphatic sac tumor: CPA involved if large
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- Cystic meningioma
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- Idealized imaging protocol in evaluating cystic CPA masses
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- T1 C+ fat-saturated MR is gold standard
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- Contrast helps differentiate solid from cystic components of tumors, such as vestibular or facial nerve schwannoma & hemangioblastoma
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- DWI for possible epidermoid cyst (restricted diffusion)
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- T2 thin-section, high-resolution MR
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- Also sorts out solid and cystic components of lesions
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- Helps with cranial nerve & vascular anatomy
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- ## Helpful Clues for Common Diagnoses
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- **Epidermoid Cyst**
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- Key facts
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- Definition: Congenital rest of epithelial tissue in CPA
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- Imaging findings
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- Insinuating or scalloping brainstem margin
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- T1 MR: Iso- to slightly hyperintense relative to CSF
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- T1 C+ MR: Typically nonenhancing cyst; may be hard to see
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- Minimal marginal cyst enhancement in 25%
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- Soft tissue enhancement present in rare cases of malignant degeneration to squamous cell carcinoma; PET avidity can help confirm suspicion
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- T2 MR: High-signal, well-circumscribed CPA mass
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- FLAIR: Lack of complete fluid suppression
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- DWI: Restricted diffusion (high signal) makes diagnosis
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- **Arachnoid Cyst**
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- Key facts
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- Definition: Congenital lesion resulting from failure of embryonic meninges to merge results in cyst between split arachnoid membrane
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- Imaging findings
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- Fills cistern with rounded margins
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- T1 C+ MR: No enhancement
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- FLAIR: Lesion attenuates (black like CSF)
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- DWI: Isointense to CSF (no restriction)
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- ## Helpful Clues for Less Common Diagnoses
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- **Vestibular Schwannoma W****ith Intramural Cyst(s)**
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- Key facts
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- Definition: Vestibular schwannoma may have either intramural or extramural cysts associated
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- Imaging findings
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- Solid CPA-IAC mass with intramural cysts
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- Bone CT: Larger lesions flare medial IAC component
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- T1 C+ MR: Enhancing solid tumor component ± intramural cysts (common) ± extramural cyst (rare)
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- Microhemorrhages on T2* GRE or SWI favor schwannoma over meningioma
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- **Hemangioblastoma**
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- Key facts
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- Definition: Benign tumor composed of stromal cells in small blood vessels of CNS
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- Adult with intraaxial posterior fossa mass abutting pia
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- Associated with von Hippel Lindau (VHL) in 25-40%
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- Supratentorial hemangioblastomas more likely VHL related
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- Imaging findings
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- Cerebellar cystic & solid tumor
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- T1 C+ MR: 60% of tumors with solid enhancing & cystic components (40% solid only)
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- **Large Endolymphatic Sac Anomaly (IP-II)**
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- Key facts
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- Bilateral congenital sensorineural hearing loss that appears in child with cascading hearing loss pattern
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- Most common congenital imaging abnormality
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- Recommendation to avoid contact sports
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- Imaging findings
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- Bone CT: Enlarged bony vestibular aqueduct
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- T2 high-resolution MR: Enlarged endolymphatic sac & duct + mild cochlear malformation (modiolar deficiency, deficient apical septation, & scalar chamber asymmetry)
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- **Neurocysticercosis**
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- Key facts
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- Definition: Intracranial infection caused by pork tapeworm (*Taenia solium*)
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- Imaging findings
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- Cysts with "dots" inside
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- Appearance varies with stage
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- T1 C+ MR: Cysts with enhancing thin or thick wall
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- May be associated with hydrocephalus
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- ## Helpful Clues for Rare Diagnoses
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- **Vestibular Schwannoma W****ith Extramural Cyst**
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- Key facts
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- Vestibular schwannoma with extramural cyst
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- Cyst may be "trapped CSF" or actual arachnoid cyst
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- Neurootologists call extramural cyst "herald cyst"
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- Imaging findings
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- CPA-IAC mass with extramural cyst
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- Bone CT: Large lesions flare IAC medial component
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- T1 C+ MR: Enhancing solid tumor component ± extramural cyst
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- Microhemorrhages on T2* GRE or SWI favor schwannoma over meningioma
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- **Facial Nerve Schwannoma in CPA-IAC W****ith Cyst**
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- Key facts
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- Rare CPA-IAC mass with labyrinthine tail involving labyrinthine segment of facial nerve canal
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- Often presents with hearing loss before facial nerve symptoms
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- Imaging findings
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- Bone CT: Labyrinthine segment of facial nerve may be enlarged
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- T1 C+ MR: Enhancing tubular mass in CPA-IAC & labyrinthine segment of facial nerve; intramural or extramural cyst visible
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- **Schwannoma, Trigeminal, Skull Base**
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- Key facts
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- Most common presentation is ipsilateral facial pain
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- Imaging findings
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- CPA cystic enhancing mass with tail extending toward or into Meckel cave is characteristic
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- Look for denervation of masticator space muscles
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- **Neurenteric****C****yst**
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- Key facts
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- Arises at time of notochordal development during transitory existence of neurenteric canal
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- Benign endodermal lesion of CNS
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- Often presents as incidental rounded to ovoid mass in prepontine cistern
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- Imaging findings
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- MR shows intermediate- to high-signal T1 prepontine "cystic" mass
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- **Jugular Foramen Schwannoma W****ith Intramural Cyst**
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- Key facts
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- Presents with mixture of 9-12 cranial neuropathy
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- Imaging findings
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- Bone CT: Enlarged, sharply marginated jugular foramen
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- T1 MR: Iso-g to hyperintense compared to CSF
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- T1 C+ MR: Enhancing mass with intramural cysts arising from jugular foramen
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- Intramural cysts in 25% of jugular foramen schwannomas
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- Other MR findings: Mass projects superomedially into CPA cistern, often with brainstem compression
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- **Cystic Metastasis in CPA**
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- Key facts
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- Usually in patients with known primary cancer
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- Imaging findings
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- T1 C+ MR: Enhancing mass with cystic component may mimic schwannoma or cystic meningioma
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- Likely to exhibit rapid growth pattern and more symptoms, such as facial nerve palsy, than benign tumors like schwannoma
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- **Endolymphatic Sac Tumor**
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- Key facts
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- Sporadic or associated with VHL
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- Bilateral tumors &/or concurrent hemangioblastoma indicates VHL
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- Imaging findings
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- Bone CT: Permeative destruction of posterior petrous temporal bone centered at vestibular aqueduct
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- T1 MR: Hyperintense foci due to internal hemorrhage are characteristic
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- T1 C+ MR: Partly cystic, heterogenous enhancing mass
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- DOTATATE scan may show mild uptake due to somatostatin receptor type 2A expression in tumor vasculature not tumor cells
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- **Meningioma, Cystic**
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- T1 C+ MR: Rare, heterogeneous, partly cystic enhancing mass
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- Rare meningioma variant that mimics schwannoma; most are clear cell subtype
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## References
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# Selected References
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1. [Ali NE et al: Natural history of cystic vestibular schwannomas. Ann Otol Rhinol Laryngol. 132(7):795-9, 2023](http://www.ncbi.nlm.nih.gov/pubmed/?term=35993287%5Bpmid%5D)
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1. [Adachi S et al: Unusual imaging characteristics of cystic meningioma in cerebellopontine angle. Neuroradiol J. 35(6):777-9, 2022](http://www.ncbi.nlm.nih.gov/pubmed/?term=35503008%5Bpmid%5D)
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1. [Geng Y et al: Endolymphatic sac tumour: exploring the role of CT and MRI features in the diagnosis of 22 cases. Clin Radiol. 77(8):e592-8, 2022](http://www.ncbi.nlm.nih.gov/pubmed/?term=35643739%5Bpmid%5D)
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1. [Talukdar R et al: Endolymphatic sac tumor: single-institution series of seven cases with updated review of literature. Eur Arch Otorhinolaryngol. 279(5):2591-8, 2022](http://www.ncbi.nlm.nih.gov/pubmed/?term=34410472%5Bpmid%5D)
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1. [Parlak S et al: 3 Tesla MR imaging of the large endolymphatic duct and sac anomaly with audiological correlation. Eur J Radiol. 145:110064, 2021](http://www.ncbi.nlm.nih.gov/pubmed/?term=34839211%5Bpmid%5D)
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1. [Saigal G et al: Utility of microhemorrhage as a diagnostic tool in distinguishing vestibular schwannomas from other cerebellopontine angle (CPA) Tumors. Indian J Otolaryngol Head Neck Surg. 73(3):321-6, 2021](http://www.ncbi.nlm.nih.gov/pubmed/?term=34471620%5Bpmid%5D)
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1. [Lou R et al: 68Ga-DOTATATE uptake in an endolymphatic sac tumor: radiologic-pathologic correlation. Clin Nucl Med. 45(7):563-5, 2020](http://www.ncbi.nlm.nih.gov/pubmed/?term=32433163%5Bpmid%5D)
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1. [Connor SEJ et al: Is CT or MRI the optimal imaging investigation for the diagnosis of large vestibular aqueduct syndrome and large endolymphatic sac anomaly? Eur Arch Otorhinolaryngol. 276(3):693-702, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=30635710%5Bpmid%5D)
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1. [Eliezer M et al: Clinical and radiological characteristics of malignant tumors located to the cerebellopontine angle and/or internal acoustic meatus. Otol Neurotol. 40(9):1237-45, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=31469787%5Bpmid%5D)
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1. [Le H et al: Clinicoradiologic characteristics of endolymphatic sac tumors. Eur Arch Otorhinolaryngol. 276(10):2705-14, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=31197530%5Bpmid%5D)
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1. [Touska P et al: Temporal bone tumors: an imaging update. Neuroimaging Clin N Am. 29(1):145-72, 2019](http://www.ncbi.nlm.nih.gov/pubmed/?term=30466638%5Bpmid%5D)
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1. [Schnack DT et al: Sporadic endolymphatic sac tumor-a very rare cause of hearing loss, tinnitus, and dizziness. J Int Adv Otol. 13(2):289-91, 2017](http://www.ncbi.nlm.nih.gov/pubmed/?term=28716765%5Bpmid%5D)
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1. [Agarwal A: Intracranial trigeminal schwannoma. Neuroradiol J. 28(1):36-41, 2015](http://www.ncbi.nlm.nih.gov/pubmed/?term=25924170%5Bpmid%5D)
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1. [Dispenza F et al: Imaging of vestibular schwannoma with prevalent cystic component: cystic vestibular schwannoma. Otol Neurotol. 30(5):681-2, 2009](http://www.ncbi.nlm.nih.gov/pubmed/?term=18716565%5Bpmid%5D)
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1. [Piccirillo E et al: Cystic vestibular schwannoma: classification, management, and facial nerve outcomes. Otol Neurotol. 30(6):826-34, 2009](http://www.ncbi.nlm.nih.gov/pubmed/?term=19704364%5Bpmid%5D)
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1. [Zhang L et al: Trigeminal schwannomas: a report of 42 cases and review of the relevant surgical approaches. Clin Neurol Neurosurg. 111(3):261-9, 2009](http://www.ncbi.nlm.nih.gov/pubmed/?term=19081670%5Bpmid%5D)
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1. [Bonneville F et al: Imaging of cerebellopontine angle lesions: an update. Part 1: enhancing extra-axial lesions. Eur Radiol. 17(10):2472-82, 2007](http://www.ncbi.nlm.nih.gov/pubmed/?term=17562049%5Bpmid%5D)
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1. [Bonneville F et al: Imaging of cerebellopontine angle lesions: an update. Part 2: intra-axial lesions, skull base lesions that may invade the CPA region, and non-enhancing extra-axial lesions. Eur Radiol. 17(11):2908-20, 2007](http://www.ncbi.nlm.nih.gov/pubmed/?term=17569053%5Bpmid%5D)
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1. [Kiliçkesmez O: Endolymphatic sac tumor in a patient with von Hippel-Lindau disease: MR imaging findings. Diagn Interv Radiol. 12(1):14-6, 2006](http://www.ncbi.nlm.nih.gov/pubmed/?term=16538578%5Bpmid%5D)
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1. [Patel NP et al: The radiologic diagnosis of endolymphatic sac tumors. Laryngoscope. 116(1):40-6, 2006](http://www.ncbi.nlm.nih.gov/pubmed/?term=16481807%5Bpmid%5D)
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1. [Preece MT et al: Intracranial neurenteric cysts: imaging and pathology spectrum. AJNR Am J Neuroradiol. 27(6):1211-6, 2006](http://www.ncbi.nlm.nih.gov/pubmed/?term=16775266%5Bpmid%5D)
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1. [Nelson MD Jr et al: A different approach to cysts of the posterior fossa. Pediatr Radiol. 34(9):720-32, 2004](http://www.ncbi.nlm.nih.gov/pubmed/?term=15316692%5Bpmid%5D)
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1. [Bonneville F et al: Unusual lesions of the cerebellopontine angle: a segmental approach. Radiographics. 21(2):419-38, 2001](http://www.ncbi.nlm.nih.gov/pubmed/?term=11259705%5Bpmid%5D)
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1. [Davidson HC et al: MR evaluation of vestibulocochlear anomalies associated with large endolymphatic duct and sac. AJNR Am J Neuroradiol. 20(8):1435-41, 1999](http://www.ncbi.nlm.nih.gov/pubmed/?term=10512225%5Bpmid%5D)
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1. [Koeller KK et al: Congenital cystic masses of the neck: radiologic-pathologic correlation. Radiographics. 19(1):121-46; quiz 152-3, 1999](http://www.ncbi.nlm.nih.gov/pubmed/?term=9925396%5Bpmid%5D)
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1. [Lau KY et al: MRI demonstration of subarachnoid neurocysticercosis simulating metastatic disease. Neuroradiology. 40(11):724-6, 1998](http://www.ncbi.nlm.nih.gov/pubmed/?term=9860122%5Bpmid%5D)
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1. [Mukherji SK et al: Papillary endolymphatic sac tumors: CT, MR imaging, and angiographic findings in 20 patients. Radiology. 202(3):801-8, 1997](http://www.ncbi.nlm.nih.gov/pubmed/?term=9051037%5Bpmid%5D)
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1. [Tong KA et al: Large vestibular aqueduct syndrome: a genetic disease? AJR Am J Roentgenol. 168(4):1097-101, 1997](http://www.ncbi.nlm.nih.gov/pubmed/?term=9124122%5Bpmid%5D)
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1. [Friedman DP et al: Vascular neoplasms and malformations, ischemia, and hemorrhage affecting the spinal cord: MR imaging findings. AJR Am J Roentgenol. 162(3):685-92, 1994](http://www.ncbi.nlm.nih.gov/pubmed/?term=8109522%5Bpmid%5D)
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1. [Kollias SS et al: Cystic malformations of the posterior fossa: differential diagnosis clarified through embryologic analysis. Radiographics. 13(6):1211-31, 1993](http://www.ncbi.nlm.nih.gov/pubmed/?term=8031352%5Bpmid%5D)
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1. [Smirniotopoulos JG et al: Cerebellopontine angle masses: radiologic-pathologic correlation. Radiographics. 13(5):1131-47, 1993](http://www.ncbi.nlm.nih.gov/pubmed/?term=8210595%5Bpmid%5D)
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## Images
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### Selected Images
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**Epidermoid Cyst**
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*Axial T1 C+ MR reveals a low signal intensity, nonenhancing epidermoid cyst that insinuates into the foramen of Luschka <img src='img/arrows/WS.png'/> and along the right cerebellar hemisphere <img src='img/arrows/WO.png'/>. DWI MR sequence would show restricted diffusion. FLAIR would show lack of complete fluid suppression.*
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**Epidermoid Cyst**
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*Axial T1 C+ MR reveals a low signal intensity, nonenhancing epidermoid cyst that insinuates into the foramen of Luschka <img src='img/arrows/WS.png'/> and along the right cerebellar hemisphere <img src='img/arrows/WO.png'/>. DWI MR sequence would show restricted diffusion. FLAIR would show lack of complete fluid suppression.*
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**Arachnoid Cyst**
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*Axial T1 C+ FS MR demonstrates a right cerebellopontine angle (CPA) cistern arachnoid cyst <img src='img/arrows/WS.png'/> displacing the proximal facial and vestibulocochlear nerves anteriorly <img src='img/arrows/WO.png'/>.*
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**Vestibular Schwannoma With Intramural Cyst(s)**
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*Axial T1 C+ MR shows a large enhancing vestibular schwannoma projecting from the internal auditory canal (IAC) <img src='img/arrows/WS.png'/> into the CPA cistern. The tumor has a large intramural cyst <img src='img/arrows/WO.png'/> that compresses the brainstem and cerebellum.*
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**Vestibular Schwannoma With Intramural Cyst(s)**
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*Axial T2 MR shows a heterogeneous CPA mass <img src='img/arrows/WS.png'/> extending into the left internal auditory canal. Note numerous large intramural tumor cysts <img src='img/arrows/WC.png'/>.*
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**Hemangioblastoma**
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*Axial T1 C+ FS MR shows a superficial, intracerebellar mixed cystic-solid hemangioblastoma projecting into the left CPA cistern area. The solid nodule <img src='img/arrows/WS.png'/> is avidly enhancing.*
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**Large Endolymphatic Sac Anomaly (IP-II)**
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*Axial T2WI MR shows a large endolymphatic sac <img src='img/arrows/WS.png'/> within the posterior wall of the temporal bone. CT (not shown) would reveal a large bony vestibular aqueduct in this patient with large endolymphatic sac anomaly.*
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**Neurocysticercosis**
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*Axial T1 C+ FS MR demonstrates a cystic mass in the right CPA cistern with a peripherally enhancing wall <img src='img/arrows/WS.png'/>. Adjacent enhancing, thickened meninges <img src='img/arrows/WO.png'/> are also seen.*
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**Vestibular Schwannoma With Extramural Cyst**
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*Axial T2WI MR shows a vestibular schwannoma <img src='img/arrows/WS.png'/> projecting from the IAC into the CPA cistern. An associated (extramural) arachnoid cyst is visible <img src='img/arrows/WO.png'/> compressing the brainstem and 4th ventricle <img src='img/arrows/WC.png'/>.*
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**Facial Nerve Schwannoma in CPA-IAC With Cyst**
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*Axial T1 C+ MR reveals an enhancing CPA mass <img src='img/arrows/WS.png'/>, with intramural cysts, which projected into the IAC but did not involve the labyrinthine segment. Note atrophy of the right platysma muscle <img src='img/arrows/BS.png'/> from CNVII denervation.*
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**Schwannoma, Trigeminal, Skull Base**
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*Axial T1 C+ MR demonstrates a large CPA cystic mass "pointing" toward the Meckel cave <img src='img/arrows/WS.png'/>, providing a clue to the origin of this mass. Note chronic denervation changes of volume loss and fatty infiltration in the left suprazygomatic masticator space <img src='img/arrows/WO.png'/> compared to the right <img src='img/arrows/WC.png'/>, partly seen here.*
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**Neurenteric Cyst**
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*Axial T1WI MR shows a small mass anterior to the pontomedullary junction <img src='img/arrows/WS.png'/>. The neurenteric cyst is well delineated, demonstrating nearly isointense signal to brain, and does not enhance significantly.*
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**Jugular Foramen Schwannoma With Intramural Cyst**
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*Axial T2 FS MR reveals a large, sharply marginated lesion expanding the left jugular foramen <img src='img/arrows/WO.png'/>. The high-signal mass projects medially into the low CPA cistern where it compresses the brainstem <img src='img/arrows/WS.png'/>.*
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**Cystic Metastasis in CPA**
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*Parasagittal T1 C+ FS MR shows a heterogeneous, cystic enhancing mass <img src='img/arrows/WC.png'/> in the right CPA <img src='img/arrows/WS.png'/>. Adjacent brain edema is noted <img src='img/arrows/WO.png'/>. Although the mass might mimic a cystic schwannoma, the presence of a 2nd enhancing mass and a clinical history of lung cancer helps establish diagnosis of metastasis.*
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**Endolymphatic Sac Tumor**
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*Axial high-resolution T2 MR shows a heterogeneous cystic CPA mass <img src='img/arrows/WS.png'/>. The key to diagnosis is identifying the mass origin from the posterior temporal bone in the expected location of the endolymphatic sac.*
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### Additional Images
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**Vestibular Schwannoma With Extramural Cyst**
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*Axial T1 C+ MR shows an atypical heterogeneously enhancing left vestibular schwannoma <img src='img/arrows/WC.png'/> with an associated arachnoid cyst <img src='img/arrows/WS.png'/>.*
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**Jugular Foramen Schwannoma With Intramural Cyst**
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*Coronal T1 C+ MR shows variant MR case of a jugular foramen schwannoma with intramural cyst <img src='img/arrows/WO.png'/> and very large cisternal component. The jugular foramen connection is seen on the next image.*
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**Jugular Foramen Schwannoma With Intramural Cyst**
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*Coronal T1 C+ MR reveals an enhancing schwannoma in the jugular foramen <img src='img/arrows/WS.png'/>. The tumor projects superomedially to fill the CPA cistern <img src='img/arrows/WO.png'/> and compress the brainstem.*
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**Schwannoma, Trigeminal, Skull Base**
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*Axial T1 C+ MR in a patient presenting with left facial pain demonstrates a peripherally enhancing cystic mass in the left CPA with a vector of spread extending towards Meckel cave <img src='img/arrows/WS.png'/>, that was the clue to its origin.*
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**Neurocysticercosis**
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*Coronal T1 C+ FS MR shows multiple cysts in the right CPA cistern <img src='img/arrows/WS.png'/> causing mass effect on the brainstem. Secondary hydrocephalus is present.*
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**Hemangioblastoma**
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*Axial T2WI MR reveals an intracerebellar high signal hemangioblastoma <img src='img/arrows/WS.png'/> projecting into the CPA cistern area. Contrast is required to define enhancing nodule if present.*
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**Jugular Foramen Schwannoma With Intramural Cyst**
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*Axial T1 C+ MR demonstrates an ovoid enhancing mass in the low CPA cistern <img src='img/arrows/WS.png'/>. Multiple intramural cysts suggest the diagnosis of schwannoma. Extension into the jugular foramen <img src='img/arrows/WO.png'/> is evident.*
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**Epidermoid Cyst**
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*Axial T1 C+ MR shows nodular soft tissue enhancement <img src='img/arrows/WO.png'/> along the margins of a cystic prepontine and left CPA epidermoid cyst <img src='img/arrows/WS.png'/>, due to a rare complication: Malignant degeneration into squamous cell carcinoma.*
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**Meningioma, Cystic**
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*Axial T1 C+ MR shows a partly cystic, partly solid mass in the right CPA <img src='img/arrows/WS.png'/> and posterior Meckel cave <img src='img/arrows/WC.png'/>. Biopsy supported meningioma, which rarely may have cystic morphologies that mimic schwannoma.*
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