Endoscopic Findings of Inverted Papilloma in the Sphenoid Sinus

An inverted papilloma is a benign tumor of the nose, well known for its local invasiveness, recurrence, and malignant potential. A 57-year-old man presented at our otolaryngologic clinic with a lesion in the sphenoid sinus. An outpatient biopsy indicated an inflammatory polyp. Endoscopic sinus surgery was used to remove the mass filling the sphenoid sinus.

On operating endoscopy, we observed a convoluted mass inside the sphenoid sinus (Figure 1A), which was present along its entire wall. The mass was removed with a Freer Elevator and a curved curette. It was a white transparent convoluted mass with dimensions of 2.5 × 1.5 cm (Figure 1B).

Figure 1.

A, A whitish transparent convoluted mass is present in the left sphenoid sinus. The mass invades the right posterior ethmoid sinus, showing invasive characteristics. B, The mass removed from the sphenoid sinus was 2.5 × 1.5 cm size. IP indicates inverted papilloma; Sp, septum; ST, superior turbinate.

When the origin of an inverted papilloma is deep, as in this case (Krouse stage III), the surface of the mass is often covered with polyp, and it is not predicted by endoscopy, endoscopic biopsy, or computed tomography in the outpatient clinic ¹ (Figure 2A and B). Although the tumor can be removed without difficulty when it is small, removal of a tumor occupying most of the sphenoid sinus is difficult, as in this case. ² A variety of instruments is required, including electrocautery and diamond drilling, for complete removal to prevent recurrences. In our case, the inverted papilloma occupied most of the sphenoid sinus, so drilling could not be performed because of the risk of damage to vital organs such as the internal carotid artery and optic nerve. The patient is being monitored and, so far, there has been no recurrence over a 2-year period.

Figure 2.

A, Coronal computed tomography (CT) shows massive filling of the left sphenoid sinus. B, Sagittal CT also shows massive filling of the left sphenoid sinus. Note the erosion of the upper portion of the clivus (red arrow).