E1964. Meckel's Cave and Beyond: A Review of Trigeminal Nerve Pathologies
  1. Peter Lee; Northwell Health - Mather Hospital
This exhibit will demonstrate the imaging appearances of pathologies involving the trigeminal nerve.

Educational Goals / Teaching Points
Review the imaging anatomy of the trigeminal nerve. Illustrate imaging findings of pathologies of the trigeminal nerve on MRI and CT.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Absence of Meckel's cave (loss of the normal fluid signal in Meckel's cave, ipsilateral trigeminal nerve is hypoplastic). Trigeminal schwannoma (often heterogeneous mass with solid and cystic components, reflecting areas of cystic degeneration, mass follows long axis of cisternal trigeminal nerve and can extend into Meckel's cave).Neurosarcoidosis (nodular enhancement along cisternal trigeminal nerve and in Meckel's cave, usually associated with pulmonary findings of sarcoidosis. Isolated neurosarcoidosis without pulmonary findings is rare).Leptomeningeal carcinomatosis (enhancement along the bilateral cisternal trigeminal nerves). Adenoid cystic carcinoma (perineural spread along V1, V2 and V3, skull-base foramina and extracranial branches of the trigeminal nerve should be carefully evaluated when there is suspicion for perineural spread of tumor, perineural spread along V3 can be associated with denervation atrophy of the muscles of mastication).Aspergillosis (fungal infection can spread from the paranasal sinuses intracranially, enhancing soft tissue in the paranasal sinuses, pterygopalatine fossa, cavernous sinus, and Meckel's cave). Skull-base fracture with extension through foramen ovale, injuring V3. Mandibular fracture with extension through mandibular canal, injuring inferior alveolar nerve. Meningioma (a cerebellopontine angle mass with dural tail extends into Meckel's cave). Pituitary macroadenoma (a sellar, parasellar, and suprasellar mass invades Meckel's cave and cavernous sinus). Epidermoid cyst (a cerebellopontine angle epidermoid cyst causes lateral bowing of the cisternal trigeminal nerve and mass effect on the brainstem).

A thorough understanding of trigeminal nerve anatomy and pathologies is valuable for radiological diagnosis.