Remo Accorona - Division of Otorhinolaryngology, San Maurizio Hospital, Bolzano, Italy.
Giovanni Colombo - Department of Otorhinolaryngology, Humanitas Clinical and Research Center, Rozzano, Milano, Italy.
Marco Ferrari - Department of Otorhinolaryngology and Head and Neck Surgery, University of Brescia, Italy.
Enrico Fazio - Department of Otorhinolaryngology, University of Insubria, Varese, Italy.

Introduction: Supernumerary teeth are frequently reported in dental clinical practice; however, eruption in nasal cavities and paranasal sinuses is an extremely rare clinical entity.   Case Report: We report two cases with a history of recurrent nasal discharge and obstruction. In both cases, clinical and radiological findings confirmed the presence of an inverted supernumerary tooth erupted in the sinonasal cavities (i.e., the right nasal fossa and left maxillary sinus, respectively). We managed the cases with transnasal endoscopic approach. A survey of the English literature identified 69 documented cases with intranasal supernumerary teeth within January 1st, 1886 to December 31st, 2017.   Conclusion: Inverted supernumerary teeth should be considered among the potential causes of unilateral nasal obstruction and rhinosinusitis and included in differential diagnoses among the fibro-osseous lesions of the sinonasal cavities.

endoscopic sinonasal surgery, Inverted supernumerary tooth, Rhinosinusitis