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A Case of Maxillary Sinus Cholesteatoma Originating from the Retromaxillary Sinus Wall

Cholesteatomas are often observed in the middle ear or mastoid cavity. However, cholesteatomas in areas other than the middle ear or mastoid are extremely rare and thus are not often reported in the literature. We recently treated an 18-year-old female patient with an incidentally detected maxillary sinus mass. A paranasal sinus computed tomography examination revealed a cystic lesion in the left maxillary sinus infiltrating the posterolateral walls of the left maxillary sinus. An endoscopic operation was performed for definitive diagnosis. Histopathological examination of the mass confirmed the diagnosis of cholesteatoma. Despite the rarity of paranasal cholesteatoma in comparison with cholesteatomas in the tympanum, a few cases involving the frontal sinus have been reported. However, retromaxillary cholesteatoma is even less common than sinus cholesteatoma and is reported rarely. To our knowledge, this is the first reported case of a maxillary cholesteatoma originating from the retromaxillary area. For this reason, we present this case along with a literature review.