CT and MRI findings of tongue ptosis and atrophy should alert radiologists to potential pathology along the course of the hypoglossal nerve (cranial nerve XII), a purely motor cranial nerve which supplies the intrinsic and extrinsic muscles of the tongue. While relatively specific for hypoglossal nerve pathology, these findings do not accurately localize the site or cause of denervation. A detailed understanding of the anatomic extent of the nerve, which crosses multiple anatomic spaces, is essential to identify possible underlying pathology, which ranges from benign postoperative changes to life-threatening medical emergencies. This review will describe key imaging findings of tongue denervation, segmental anatomy of the hypoglossal nerve, imaging optimization, and comprehensive imaging examples of diverse pathology which may affect the hypoglossal nerve. Armed with this knowledge, radiologists will increase their sensitivity for detection of pathology and provide clinically relevant differential diagnoses when faced with findings of tongue ptosis and denervation.
Background
Pathologic extranodal extension (ENE) has traditionally guided the management of head and neck cancers. The prognostic value of radiographic ENE (rENE) in HPV-associated oropharyngeal squamous cell carcinoma (HPV+OPX) is uncertain.
Methods
HPV+OPX patient with adequate pre-treatment radiographic nodal evaluation, from a single institution were analyzed. rENE status was determined by neuroradiologists’ at time of diagnosis. Distant metastasis-free survival (DMFS), overall survival (OS), locoregional recurrence-free survival (LRFS) and were estimated using Kaplan-Meier methods. Cox proportional hazards models were fit to assess the impact of rENE on survival endpoints.
Results
168 patients with OPX+SCC diagnosed between April 2008 and December 2014 were included for analysis with median follow-up of 3.3 years. Eighty-eight percent of patients received concurrent chemoradiotherapy. rENE was not prognostic; its presence in HPV+OPX patients did not significantly impact OS, LRFS, or DMFS.
Conclusions
In patients with HPV+OPX, rENE was not significantly associated with OS, LRFS, or DMFS.
Active extravasation into the upper aerodigestive tract is a dramatic and potentially life-threatening complication in patients with head and neck cancers. It prompts presentation to the emergency room and subsequent urgent imaging to identify the source of hemorrhage. Imaging of these patients may be complicated by treatment-altered anatomy, posing a challenge to the emergency radiologist who needs to rapidly identify the presence of active hemorrhage and the potential source vessel. This retrospective review summarizes the clinical and imaging findings of 6 oropharyngeal and oral cavity squamous cell cancer (SCC) patients with active upper aerodigestive tract hemorrhage. Most patients had advanced stage disease and prior radiation therapy. All CECT or CTA exams on presentation demonstrated the “dot-in-sludge” sign of active extravasation, as demonstrated by a “dot” of avidly enhancing extravasated contrast material layered against a background “sludge” of non-enhancing debris in the lumen of the upper aerodigestive tract. Common sources of hemorrhage included the lingual, facial, and superior thyroidal arteries. Familiarity with these findings will help radiologists increase their accuracy and confidence in interpreting these urgent, complex examinations.