Use of transoral sonography with an endocavitary transducer in diagnosis, fine-needle aspiration biopsy, and intraoperative localization of retropharyngeal masses.

OBJECTIVE: The purpose of this article is to describe the use of transoral sonography in the diagnosis, fine-needle aspiration (FNA) biopsy, and intraoperative localization of retropharyngeal masses.
MATERIALS AND METHODS: We reviewed images and data for eight patients with a retropharyngeal mass identified on CT, MRI, or PET/CT as being suspicious for a metastatic Rouviere node. Transoral ultrasound was performed using a commercially available endorectal or endovaginal transducer. Transoral ultrasound-guided FNA biopsy was performed using a needle guide attached to the transducer shaft. Color and power Doppler imaging were used to identify the internal carotid artery and jugular vein and to plan the safest path to the targeted mass. The mass was intraoperatively localized by marking the mucosa with a permanent marker or by injecting methylene blue.
RESULTS: There were six patients with a history of thyroid cancer (five papillary cancers and one medullary cancer), one patient with a history of esthesioneuroblastoma, and one patient with no history of cancer. Transoral ultrasound imaging was successful in all eight patients. Transoral ultrasound-guided FNA biopsy was performed in four patients, and a satisfactory cytologic diagnosis was obtained in all cases, although in one of those four cases, an additional core biopsy with an 18-gauge needle was performed to completely rule out lymphoma. Six patients underwent a transoral resection of the lesion. In three of them, the lesion was localized intraoperatively by making a mark on the mucosa and in one case by adding transoral ultrasound-guided injection of methylene blue.
CONCLUSION: Transoral ultrasound can be used to visualize, sample, and localize abnormal masses in the retropharyngeal space, such as metastatic Rouviere nodes in patients with a history of head and neck cancer.