Understanding the initial approach for the care of patients with a sinonasal masses is essential for every otolaryngologist. A heightened level of suspicion is necessary when patients present with unilateral epistaxis, congestion, or ear fullness, as these symptoms are highly concerning for a mass. However, sometimes your nasal endoscopy does not correlate to clinical presentation leading to the question, “what the heck is that and what do I do next?” This session features videos and stills of rare sinonasal conditions. Interactive case presentations will be presented, and a panel of rhinology experts will discuss differential diagnosis, imaging, and treatment options. The decision to perform in-office versus intra-operative biopsy can be difficult. The panelists will discuss what they would do and how they make those decision for each vignette. The panel will also address physical exam and imaging findings that help decipher an inverting papilloma from an inflammatory polyp. Lastly, determining the presence of a nasal flare from an autoimmune vasculitis disease can be challenging; this panel of academic rhinologists will use evidence-based data and endoscopic findings to discuss indications for biopsy. Pathologies covered during the session range from inflammatory lesions to sinonasal malignancies and skull base lesions.