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57-Year-Old Woman with Headaches
This case features a 57-year-old woman presenting with headaches, ultimately diagnosed with a trigeminal schwannoma.
Imaging overview:
Axial CISS, axial T1 post-contrast fat-saturated, and sagittal T1 post-contrast fat-saturated MRI demonstrate an extra-axial enhancing mass deforming the pons, with an anterior component extending through the porus trigeminus into Meckel’s cave. The normal trigeminal nerve is visible on the contralateral side for comparison.
Clinical insight:
Trigeminal schwannomas are the second most common intracranial schwannoma after vestibular schwannomas and arise from the Schwann cells of cranial nerve V. They classically demonstrate a dumbbell appearance when they span both the posterior fossa and Meckel’s cave, though smaller lesions may be confined to a single compartment. In order of frequency, isolated involvement occurs in the cisternal, ganglionic, and postganglionic compartments, the last of which includes the cavernous sinus and skull base foramina. Recognizing the characteristic trans-compartmental extension through the porus trigeminus and the absence of a normal ipsilateral trigeminal nerve are key imaging features that distinguish this entity from other extra-axial posterior fossa masses.
Case courtesy of Daniel E. Meltzer, MD,
Mount Sinai Hospital System, NYC.