Trigeminal neuralgia is a rare manifestation of colon cancer, which can occur secondary to skull base metastatic disease. The imaging modality of choice is high resolution MRI with contrast, which accurately depicts perineural tumour spread as abnormal thickening and enhancement along the anatomic distribution of the trigeminal nerve branches, along with denervation changes in the affected muscle groups.

From the manuscript

Perineural tumour spread from colon cancer, an unusual cause of trigeminal neuropathy - a case report

Abstract
Malignant trigeminal neuralgia due to perineural spread along the branches of the trigeminal nerve, is known to commonly occur secondary to squamous cell carcinomas, lymphomas and adenoid cystic carcinomas in the head and neck region. Rarely metastases to the trigeminal nerve have been reported in breast cancer, prostate cancer and colon cancer. To the best of our knowledge trigeminal neuropathy due to skull base metastases and perineural spread along the maxillary (V2) and mandibular (V3) branches of the trigeminal nerve, secondary to colon cancer, has not been previously reported. The diagnosis in our index case was made on magnetic resonance imaging, and patient was treated accordingly by fractionated stereotactic radiotherapy, with subsequent relief of her pain.