Pathologies can affect the trigeminal nerve at any level along its course.
At its origin the trigeminal nerve may be affected by cerebrovascular disease,
inflammatory disease,
neoplasia,
infection,
and vascular malformations.
At the level of the pre-pontine cistern pathologies that cause compressive deformity of the nerve dominate,
such as tortuous or ectatic vessels and cerebellopontine angle (CPA) neoplasms.
Cavernous sinus and basal skull pathologies that affect the trigeminal nerve include aneurysms,
neoplasms such as meningioma,
schwannoma,
lymphoma,
and inflammatory disease such as sarcoidosis.
In this section we will demonstrate pathologies from the trigeminal nuclei out to the peripheral divisions in a segmental anatomical approach.
Fig. 16: Figure 16.1 – 16.6 MR images demonstrating metastasis at the right trigeminal nerve nucleus from an endometrial primary, as well as two cerebral metastases. 16.1 – Axial T1, 16.2 – Axial T1 post gadolinium (GAD), 16.3 – Axial T2 post GAD, 16.4 – Sagittal T2 post GAD, 16.5&16.6 – Coronal T1 post GAD
Fig. 17: Figure 17.1 – 17.7 Cross-sectional studies demonstrating left root entry zone lipoma. 17.1 – Axial T1, 17.2 – Axial T2, 17.3 – Axial CISS, 17.4 – Coronal FLAIR, 17.5 – Axial CT demonstrating negative Hounsfield units of lesion, 17.6 – Sagittal CISS, 17.7 – Coronal CISS
Fig. 18: Figure 18.1 – 18.5 MR images demonstrating a right pontine demyelinating plaque in a patient with multiple sclerosis presenting with trigeminal neuralgia. 18.1 Axial T2, 18.2 Axial FLAIR, 18.3 Axial ADC-DWI, 18.4 Axial B1000 of DWI showing restricted diffusion suggestive of active inflammation, 18.5, Sagittal T2
Fig. 19: Figure 19.1-19.3 MR images demonstrating right cavernoma with developmental venous anomaly (DVA). 19.1 Axial T1 showing subacute blood in cavernoma, 19.2 Axial T2, 19.3 Axial SWI showing signal dropout from cavernoma and superginous vessels from DVA.
Fig. 20: Figure 20.1 – 20.3 MR images demonstrating right trigeminal neuroma from pons to Meckel’s cave and through right foramen ovale. 20.1 Axial T1 post GAD fat saturated showing neuroma arising and coursing to an expanded Meckel’s cave. 20.2 Axial T2 showing an expanded right foramen ovale. 20.3 Coronal T1 post GAD showing an expanded right Meckel’s cave and foramen ovale.
Fig. 21: Figure 21.1-21.4 MR images demonstrating pre-pontine epidermoid tumour. 21.1 Axial T1 volume post GAD, 21.2 Axial T2, 21.3 ADC, 21.4 B1000 of DWI.
Fig. 22: Figure 22.1-22.2 MR images demonstrating left cerebellopontine angle meningioma compressing left trigeminal nerve. 22.1 Axial T1 post GAD, 22.2 Coronal T1 post GAD
Fig. 23: Figure 23.1-23.3 MR images demonstrating left CPA meningioma with compressive denervation of the trigeminal motor branches. 23.1 Axial T1 post GAD, 23.2 Coronal T1 post GAD, 23.3 Axial T2 showing asymmetric atrophy of the left masticatory muscles.
Fig. 24: Figure 24.1-24.3 MR images demonstrating right trigeminal nerve root compression by superior cerebellar artery branch. 24.1 Sagittal CISS normal left nerve root, 24.1 Sagittal shows compressive deformity upon the cisternal component of the right trigeminal nerve (long blue arrow) by a serpinginous branch of the right superior cerebellar artery (short blue arrow), 24.3 Axial CISS.
Fig. 25: Figure 25.1-25.4MR images of a patient with adenoid cystic tumour with perineural spread along the right trigeminal nerve. Fig 25.1 (axial STIR) and Figs 25.2 - 25.3 (axial T1 fat saturated post GAD) show expanded and enhancing tumour running from the root entry zone, through Meckel’s cave and the cavernous sinus, into the pterygopalatine fossa. Also note tumour spread through the infraorbital fissure (white arrow Fig 25.2) through foramen rotundum (blue arrow Fig 25.3) and through foramen ovale (green arrow Fig 25.4, coronal T1 fat saturated post GAD).
Fig. 26: Figure 26.1-26.3 MR images demonstrating right trigeminal neuroma. 26.1 Axial STIR, neuroma extending from Meckels cave through foramen rotundum into pterygopalatine fossa and through the right infraorbital foramen. 26.2 Axial T2, 26.3 Sagittal T1.
Fig. 27: Figure 27.1-27.4 MR images demonstrating large right trigeminal schwannoma. 27.1 Axial T2 schwannoma extending through expanded right foramina of ovale and rotundum. 27.2 Sagittal FLAIR, 27.3 Coronal T1, 27.4 Coronal T1 post GAD.
Fig. 28: Figure 28.1-28.2 MR images demonstrating left middle cranial fossa meningioma extending through expanded left foramen rotundum and into left pterygopalatine fossa. 28.1 Axial T1 post GAD, 28.2 Sagittal T1 post GAD.
Fig. 29: Figure 29.1-29.3 MR images of a child with metastatic and leptomeningeal spread of CNS-type primitive neuroectodermal tumour (PNET) of the pineal gland (pineoblastoma). Fig 29.3, sagittal T1 post GAD shows the original pineal gland tumour with additional bulky metastatic deposits in the sella and at the foramen of Magendie. Figs 29.1 & 29.2 (axial volume T1 post GAD) demonstrate abnormal enhancement and expansion of the trigeminal nerves bilaterally but worse on the right. Note the expanded right Meckel’s cave (black arrow) and also the leptomeningeal spread involving the VII and VIII nerve complexes bilaterally (white arrows).
Fig. 30: Figure 30.1-30.2 MR images demonstrating right trigeminal neuroma expanding the right foramen ovale. 30.1 Axial T1 post GAD fat saturated showing part cystic part solid enhancing lesion expanding and extending through right foramen ovale. 30.2 Coronal T1 post GAD fat saturated.