Skull Base Tumor and Other CPA Tumors Workup

Updated: Jul 11, 2018
  • Author: Jack A Shohet, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Workup

Imaging Studies

See the list below:

  • Meningioma

    • Computed tomography (CT) scanning findings

      • Hyperintense compared with the cerebellum on noncontrast images

      • May demonstrate calcifications within or at the periphery of the tumor

      • May be a broad attachment to the petrous ridge

      • Less likely to show enlargement of the internal auditory canal (IAC) than vestibular schwannomas

    • MRI findings

      • Variable intensity on T2-weighted images and either isointense or slightly hypointense to brain on T1-weighted images

      • Can be heterogeneous as a result of calcifications and cystic foci within the tumor

      • Dural tail sign, characterized by enhancement of the dura adjacent to an enhanced primary lesion, possible on contrast-enhanced MRI

  • Epidermoid

    • CT scanning findings

      • Hypointense to brain

      • Do not enhance (enhancement suggests an associated malignancy or infection)

      • Irregular margins with variable involvement of IAC

    • MRI findings

      • Heterogeneous and hypointense to brain on T1-weighted images

      • Homogeneous and isointense or hyperintense to brain on T2-weighted images

      • Nonenhancing (allows them to be differentiated from schwannomas, meningiomas, and chondromas, which have similar intensity characteristics)

  • Facial nerve schwannoma

    • CT scanning findings

      • Identical to vestibular schwannoma within the IAC except for possible anterosuperior IAC erosion or erosion of facial nerve canal in labyrinthine segment

      • May have enlargement of geniculate ganglion and fallopian canal (more common)

    • MRI findings

      • Isointense or mildly hypointense to brain on T1-weighted images

      • Mildly hyperintense to brain on T2-weighted images

      • Enhances with gadolinium contrast

  • Lower cranial nerve schwannoma

    • Enlargement of jugular foramen with cranial nerve IX, X, and XI tumors

    • Enlargement of hypoglossal canal with cranial nerve XII tumors

  • Arachnoid cyst [3]

    • CT scanning findings

      • Typically smooth surface lesion isointense with CSF

      • Nonenhancing

    • MRI findings

      • Isointense or hypointense with brain on T1-weighted images

      • Hyperintense to brain on T2-weighted images

  • Cerebral angiography

    • Cerebral angiography is used when involvement of a large vessel is suspected or preoperative embolization is required.

    • It is used to assess patency in vessels encased by tumor.

    • Balloon test occlusion can aid in determining likelihood of catastrophic stroke if internal carotid artery sacrifice is contemplated.

    • Preoperative embolization can be performed in vascular tumors to effectively decrease amount of blood loss.