A Case of Secondary Trigeminal Neuropathy Due to Local Malignant Invasion of the Maxillary and Mandibular Nerves at the Skull Base: A Case Report With Review of Differential Diagnosis

Trigeminal neuropathies (TNp) are a group of well-characterized disorders that involve damage to or infiltration of the trigeminal nerve. The underlying etiology of trigeminal neuropathy can be traumatic, inflammatory, autoimmune, paraneoplastic, malignant, and very rarely infectious. We present a case of trigeminal neuropathy due to local malignant invasion of the mandibular nerve with mandibular nerve enhancement at the foramen ovale and foramen rotundum. In the process, we review various etiologies of trigeminal neuropathy associated with trigeminal nerve involvement at the foramina. We emphasize the importance of a comprehensive evaluation in patients with trigeminal neuropathy, which includes searching for perineural spread or invasion by a local head and neck malignancy, as well as ruling out an inflammatory or autoimmune etiology. Our case also demonstrates that a higher field strength magnet can reveal pathology unseen with a lower field strength magnet.