An 83-year-old woman was referred with right-side nasal obstruction. The CT scan showed a 60×45×43 mm mass arising from the nasal septum. MRI imaging indicated a smooth and encapsulated mass partial cystic formation involving 30×30×24 mm. A pre-operative definitive diagnosis could not be made despite two biopsies. We performed an endoscopic intranasal operation in combination with a midfacial degloving approach. The post-operative final diagnosis was pleomorphic adenoma (PA) of the nasal septum. Nasal septal PA is exceedingly rare, and only a few cases of giant PA tumor have been reported previously. In this case, we could achieve complete en bloc excision via minimal invasive surgery without facial skin incision. Intranasal PAs have a pathologic feature which seems to be composed of higher epithelial and lower stromal components than PAs of the major salivary glands. The possibility of PA should be kept in mind when assessing nasal cavity tumors that are rich in epithelial constituents. Sometimes small cysts are formed in PAs, while a cyst large enough to be recognized macroscopically is rare. This is the first case report of a nasal septum PA accompanied with cyst formation.
