E4610. Imaging Surveillance of Head/Neck Perineural Spread
  1. Maram Alafif; University of California San Diego Health
  2. Parag Sanghvi; University of California San Diego Health
  3. Julie Bykowski; University of California San Diego Health
Perineural spread (PNS) along cranial nerves and their branches is different from pathologic findings of perineural invasion at the primary tumor site, and is a poor prognostic factor. Imaging evaluation of cranial nerves after resection or radiation therapy can be difficult without a baseline available for comparison, given mimics such as neuromas, radiation related neuropathy, and denervation changes related to initial tumor involvement or treatment. PNS recurrence may be able to be re-irradiated, however correlation with prior treatment fields is necessary due to toxicity.

Educational Goals / Teaching Points
Target audience is residents, Neuroradiology fellows and Radiologists who review surveillance imaging for head/neck cancer patients. Goal is to refresh the need to include PNS in search patterns, reiterate importance of contrast enhanced MRI prior to and as new baseline after therapy for accurate PNS surveillance, and review of patterns of post-treatment cranial nerve enhancement.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
This educational exhibit is a case-based review of contrast enhanced MRI in the setting of surveillance post-treatment of head/neck cancer perineural spread, to illustrate: cranial nerve enhancement within radiation field, post-resection neuroma, extracranial perineural spread, progression on additional cranial nerves, delayed perineural spread, surveillance of perineural spread on immunotherapy, and leptomeningeal carcinomatosis as mimic of PNS.

Perineural spread (PNS) along cranial nerves and their branches should be defined on post-contrast MRI prior to resection or radiation therapy, to define the extent of disease. Post-radiation neuritis and post-resection neuroma can be mimics of PNS, and require correlation with treatment history and surveillance for stability. Any role/benefit of immunotherapy for treatment of PNS in HNSCC remains under investigation.