Fig. 1

Pre-therapeutic evaluation for TOVS. a A transnasal endoscopic view of the larynx and hypopharynx with a tumor on the right pyriform sinus. b A view in the same case as a under Valsalva maneuver, by which an expanded hypopharyngeal lumen can be observed down to the esophageal entrance. c A transnasal endoscopic view of a superficial tumor on the posterior wall of the hypopharynx. d A view in the same case as c using narrow band imaging, by which loss of typical intra-epithelial papillary capillary loop (IPCL) can be visualized as a brownish area. e A normal CT image of the case with an exophytic tumor on the left side of the hypopharyngeal wall. f A CT image of the same case as e under Valsalva maneuver, by which a tumor can be delineated more clearly in an expanded hypopharyngeal lumen