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Cystic schwannomas are a histological and radiological variant of schwannomas in which the tumor shows cystic degeneration, often due to necrosis, hemorrhage, or mucinous changes. They may present as partially or predominantly cystic lesions, especially when large.
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| Modality | Imaging features |
|---|---|
| CT | • Well-defined cystic mass. |
| • May show internal septations or mural nodules. | |
| • Peripheral or heterogeneous enhancement of solid components. | |
| • Bone changes (if adjacent): Smooth remodeling, foraminal widening. | |
| MR | • T1: Hypointense cystic areas; solid components iso- to hypointense. |
| • T2: Hyperintense cystic areas with fluid signal; solid regions may appear hyperintense with internal heterogeneity. | |
| • Post-contrast T1: Peripheral rim enhancement, mural nodule enhancement, or septal enhancement. |
Classification of cystic vestibular schwannomas as having a multiple large thin-walled cysts, b multiple small thick-walled cysts, c single large thin-walled cyst, d larger central thick-walled cyst, and e mixed pattern of small and large cysts
Peker, S., Samanci, Y., Ozdemir, I.E. et al. Long-term results of upfront, single-session Gamma Knife radiosurgery for large cystic vestibular schwannomas. Neurosurg Rev 46, 2 (2023). https://doi.org/10.1007/s10143-022-01911-3
Key signs:
Fluid-fluid levels rarely seen: https://doi.org/10.3174/ajnr.A1511 https://doi.org/10.1016/j.clinimag.2008.11.001
Cystic schwannoma in a 47 year female who presented with a complaint of dull progressive neck pain for the past two months. a. Initial NCCT examination revealed a multiloculated cystic lesion in the left cerebellopontine angle (CPA), iso-attenuating to the CSF. b-f. MR evaluation one week later demonstrated a multiloculated cystic lesion with internal thin septations (b, c) with an ice cream cone appearance into the left internal acoustic meatus along with the left vestibulocochlear nerve (CN VIII), suggesting the diagnosis of a cystic schwannoma. The cystic content showed high signal on FLAIR (e) and T2-weighted (f) sequences and a low signal on T1-weighted sequence (g) with internal fluid-fluid levels (arrows in f).
Case courtesy Dr Tepty Kutum, MD, Dr Satyam Sharma, Dr Marrie Pegu // #SMCHCase
Common sites:
| Location | Features |
|---|---|
| Spinal Cystic Schwannoma | • Intradural extramedullary location. |
| • Causes expansion of neural foramina or scalloping of vertebral bodies. | |
| • MRI shows cystic areas compressing the cord or cauda equina. | |
| Vestibular (CPA) Cystic Schwannoma | • Often larger at presentation. |
| • May mimic an arachnoid cyst or cystic meningioma. | |
| • Enhancing mural nodule in the internal auditory canal (IAC) is a helpful clue. | |
| Retroperitoneal Cystic Schwannoma | • Large, encapsulated masses with cystic degeneration. |
| • Differential includes lymphangioma, cystic degeneration in neurofibroma or sarcoma. |
A Lateral thoracic X-ray showing no bone abnormalities. Sagittal B T1- and C T2-weighted MRI showing a round lesion with lower and higher signal intensities, respectively. Post-contrast D axial and E sagittal T1-weighted images showing the well-defined cystic mass with thick circumferential wall enhancement. F Axial T2 images showing the location of the intra-dural extra-medullary lesion with severe compression of the thoracic segment of the cord.
Samman, A.M., Bardeesi, A.M. & Alzahrani, M.T. Thoracic cystic schwannoma: case report and review of literature. Spinal Cord Ser Cases 7, 7 (2021). https://doi.org/10.1038/s41394-020-00376-0