INTRODUCTION

Fungiform papilloma, inverted papilloma and oncocytic Schneiderian papilloma are three morphologically separate le­sions arising from the Schneiderian membrane (Hyams 1971). Oncocytic type is the rarest which comprises about 3~5% and occurs mostly in patients over 50 years of age (Cunningham et al. 1987). Characteristic histological ap­pearance of multilayered eosinophilic epithelium with mixed exophytic and in­verted growth pattern differentiates this tumour from the other type of papillomas. The clinical be­havior is similar to inverted papilloma but has a higher rate of local recurrence and malignant transformation (Kaufman et al. 2002).

CASE REPORT

A 78 year old lady presented with recur­rent unilateral epistaxis associated with progressive nasal blockage for six years. She denied facial numbness or visual symptoms. Clinically there was no op­thalmoplegia. Nasal endoscopy showed a friable mass arising from the left middle meatus filling the nasal cavity and naso­pharynx (Figure 1). Otherwise, ear, throat, head and neck examination was unre­markable.

An intranasal biopsy was taken which showed histological features of oncocytic papilloma. Computed tomography of the paranasal sinuses showed a soft tissue mass filling the left maxillary antrum, ex­tending into the nasal cavity and naso­pharyx with widening of the maxillary ostium. There was no bony erosion noted which would suggest malignancy.

The patient underwent an endoscopic medial maxillectomy for tumour excision. Intraoperative findings revealed that the tumour mass was occupying the left na­sal cavity with its attachment within the maxillary sinus. The surgery started with debulking of the tumour with a powered mi­crodebrider until visualization of the tu­mour protruding through the maxillary ostium. The procedure then entailed a radical inferior turbinectomy following which an L-shaped osteotomy was per­formed. The vertical limb corresponded to the anterior wall of the maxilla and the horizontal limb corresponded to the floor of the maxillary sinus. The tumour was then removed using a microdebrider and its origin traced to the posteromedial wall of the maxillary sinus. Complete tumour excision was achieved with preservation of healthy surrounding mucosa.

Histopathological examination of the specimen revealed multiple polypoidal tissue with a central core of connective tissue composed of proliferating colum­nar epithelial cells with admixture of mu­cin containing cells and numerous micro­cysts (Figure 2) which was consistent with the diagnosis of oncocytic papilloma. There was no evidence of malignancy in the multiple samples of the surgical spe­cimen.

The patient had an uneventful post­op­erative recovery. She was last seen at six months post operatively and there was no recurrence noted.

DISCUSSION

Oncocytic papilloma (OCP) is derived from the Schneiderian membrane and is also called cylindrical cell papilloma or columnar cell papilloma (Hyams 1971). The etiology for OCP is unknown. There is no sex predilection, unlike in inverted and fungiform types which occur predo­minantly in males.

The most common presenting features are unilateral nose block and intermittent epistaxis. OCP always occurs unilate­r­ally, usually arising from or involving the maxillary sinus (Barnes & Bedetti 1984; Hyams 1971) in contrast to inverted pa­pilloma which often arises from the lat­eral nasal wall (Lawson et al. 1995).

Grossly, OCP appears as a fleshy pink papilloma or grey polypoidal growth. The classic histologic description of OCP is the presence of both exophytic and in­verted growth patterns, composed of multilayers of columnar cells with eosi­nophilic cytoplasm and small uniform dark nuclei. The epithelial cells of OCP are true oncocytes from the sinonasal respiratory epithelium - hence the term oncocytic Schneiderian papilloma was used. The epithelium characteristically contains small cysts filled with mucin or neutrophils (microabscess) (Barnes & Bedetti 1984; Hyams 1971).

OCP has similar clinical behaviour with the inverted type which includes a pro­pen­sity for local invasiveness, recurrence and malignant transformation. Although OCP is relatively uncommon, they have a higher rate of recurrence and malignant transformation. The recurrence rate is 33% versus 15% and malignant change is 17% versus 9% in OCP compared to inverted papilloma (Kaufman et al. 2002). The most frequent type of malignancy is invasive squamus cell carcinoma. As in inverted papilloma, the carcinoma may arise within the papilloma as evidenced by a degradation of histologic changes ranging from dysplasia to carcinoma in situ to invasive carcinoma or simply a coexistence of carcinoma with papilloma at the same anatomical site.

Complete resection of this tumour is advocated in view of the high recurrence rate and possibility of missing an associ­ated carcinoma. Much has been written on the advantages of endoscopic medial maxil­lectomy over the external approach. En­doscopic approach has superior mag­nifi­cation and angled view for better visu­ali­zation and delineation of tumour mar­gins. Endoscopic sinus surgery including en­doscopic medial maxillectomy is a vi­able primary treatment alternative for si­no­nasal inverted papilloma with compa­rable recurrence rates to external ap­proaches (Wormald et al. 2003; Nicolai et al. 2006). Tumours arising from an­teromedial and anterior wall of the max­illary sinus can be addressed by an en­doscopic medial maxillectomy in which removal of the medial wall of the maxilla (including the inferior turbinate) up to its anterior wall is performed. It can be com­bined with a canine fossa puncture to resect disease arising from the lateral wall and floor of the maxillary sinus (Wormald et al. 2003). It can also provide excellent and com­plete exposure of the maxillary sinus and ethmoids without re­moving the lamina papyracea, the medial floor of the orbit, the anterior maxillary wall, and the frontal process of maxilla with preserva­tion of the medial palpebral ligament, unlike open medial maxillec­tomy (Sadeghi et al. 2003). Lack of an external scar, shorter operative time and reduced bleeding re­duces morbidity and hospital stay. How­ever, an open ap­proach is advocated in tumours extend­ing into the orbit, frontal sinus and intra­cranium as well as those with wide at­tachment within the sinonasal complex (Tufano & Thaler 1999).

In our patient the endoscopic approach was opted in view of the limited tumour extension which was viable for complete excision via the endoscopic technique. Preoperative imaging was also not sug­gestive of any associated malignancy where an open approach would be advo­cated. Endoscopic tumour excision also affords shorter hospital stay with no as­sociated morbidity which was ideal in our elderly patient.

Post operative routine endoscopic sur­veillance is important regardless of the surgical approach to detect early recur­rence of tumours that may be harbouring a malignancy.

CONCLUSION

Oncocytic papilloma is uncommon and has a higher rate of recurrence and ma­lignant transformation compared to in­verted papilloma. It should be considered in the differential diagnosis of unilateral polypoid nasal lesions especially in el­derly patients. Endoscopic medial maxil­lectomy can be the procedure of choice as it is minimally invasive and provides good tumour clearance in selected cases.