DISCUSSION
There are sparse descriptions in the literature regarding endopharyngeal ultrasonographic techniques8,9,10. All such descriptions have employed rigid endocavitary probes, which
suffer from limitations in: 1) the anatomic regions accessible to line of sight through the oral
aperture and 2) cumbersome size. Here, we present EPhus and EPhUS-guided FNA as a safe and minimally invasive technique for assessing and sampling parapharyngeal lesions not accessible by transcutaneous FNA. While EPhUS requires specialized equipment, the procedure is straight forward for surgeons familiar with endoscopy of the upper aerodigestive tract and ultrasonography. Most hospitals which provide multispecialty care are equipped with the necessary endoscopes to perform EPhUS. In this case example, a lesion of the carotid space, was successfully visualized and sampled by EPhUS. Additional spaces, which have traditionally proved hard to access by transcutaneous image (US or CT) guided FNA, yet are accessible by EPhUS include the parapharyngeal, retropharyngeal and pterygomandibular spaces (Figures 2A-B).
In conclusion, EPhUS and EPhUS guided FNA can be a safe, minimally invasive approach for visualization and biopsy of lesions in the parapharyngeal, retropharyngeal and pterygomandibular spaces, which have traditionally been difficult to access with transcutaneous image guided FNA.
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Figure legends
Figure 1. A 61-year-old woman with an incidentally found left neck mass.
  1. Contrast-enhanced CT demonstrates a well-demarcated lesion (arrows ) with a punctate calcification (arrowhead ) displacing the internal and external carotid arteries anteromedially and internal jugular vein posterolaterally. Note the lesion is surrounded by great vessels, preventing percutaneous biopsy.
  2. Post-contrast fat-suppressed T1-weighted MR image demonstrates a rim-enhancing, predominantly non-enhancing lesion (arrows ) with a nodular enhancement (arrowhead ) at its medial portion, which may be an ideal site for biopsy.
  3. Fast-field echo MR image demonstrates foci of susceptibility effect (arrowheads ) within the lesion (arrows ), suggestive of microhemorrhage.
  4. A Crow-Davis is used to expose the pharynx. An assistant works to keep the bronchoscope in position.
  5. The endoscope is equipped with a 7.5 MHz convex ultrasound probe and a needle that is delivered through the working channel of the scope.
  6. Endoscopic Doppler ultrasonography demonstrates the lesion (arrows ) and surrounding internal and external carotid vessels (arrowheads ).
  7. Intra-procedure ultrasonography demonstrates needle (arrows ) inserted into the lesion for sampling.
Figure 2. Examples of lesions that may be accessed by EPhUS guided FNA
  1. A 53-year-old man with laryngeal cancer. Contrast-enhanced CT demonstrates a borderline-enlarged round retropharyngeal node with ill-defined boundary (arrow ).
  2. A 73-year-old woman with mandibular cancer status post resection and reconstruction. Contrast-enhanced CT demonstrates a peripherally enhancing lesion (arrow ) at the medial and posterior aspect of the right medial pterygoid muscle, concerning for recurrence.