Giant benign sinonasal squamous papilloma: Report of a case.

Abstract

We treated a patient with a giant squamous papilloma in the nasal cavity and maxillary sinus that extended through a bony defect into the oral cavity. The mass was excised with a combined endoscopic, Caldwell-Luc, and transoral approach. Lesions of this type are rare, but when they do occur, the rate of recurrence is high. Therefore, long-term followup, including endoscopic examination, is important.

Introduction

Intranasal papilloma is an uncommon benign tumor of the nasal cavity. It is approximately 1/25 as frequent as the common nasal polyp. One of its subtypes, squamous cell papilloma of the nasal cavity, usually arises from the nasal septum or the floor of the nostril. It is not considered to be premalignant, and bone erosion is uncommon. We report a case of giant squamous papilloma involving the nasal cavity and maxillary sinus that eroded the maxilla and extended into the oral cavity.

Case report

A 35-year-old Chinese man with moderate mental retardation came to the clinic with a left-sided nasal obstruction and mucopurulent discharge. Anterior rhinoscopy revealed that a firm, gray, exophytic mass was blocking the entire left nostril. A similar lesion arose from the third molar socket in the oral cavity (figure 1). Poor oral hygiene and severe dental caries were noted.

A biopsy of the superficial nasal mass showed only chronic inflammation. Computed tomography (CT) of the paranasal sinuses confirmed that a heterogeneous lesion had completely filled the left nasal cavity and maxillary sinus and had extended into the oral cavity through a large bone defect in the floor of the left maxillary sinus (figure 2).

Surgical resection was planned to rule out the presence of an underlying malignancy. Combined endoscopic, Caldwell-Luc, and transoral approaches were used to excise the tumor. At operation, the papilloma was found to arise from the floor of the left maxillary sinus. It extended into the oral cavity through a 1.5-cm bone defect in the region of the third molar socket.

The tumor was completely removed under visualization. The large cavity that remained was packed with ribbon gauze that had been soaked with bismuth iodoform paraffin paste. Paraffin section of the resected specimen showed a fibrovascular stroma covered by nondysplastic, keratinized, stratified squamous epithelium. The epithehum was hyperkeratotic, with areas of acanthosis and papillomatosis. The diagnosis of squamous papilloma was made. There was no evidence of malignancy. No recurrence was detected during 9 months of followup.

Discussion

Intranasal papilloma is an uncommon, benign tumor of the nasal cavity. It occurs approximately 1/25 as often as the common nasal polyp. [1'2] There are four histomorphologic types of papilloma that occur in the sinuses: keratinizing squamous, fungiform, cylindrical cell, and inverted. [3] The squamous papilloma is an epidermal lesion similar to those found on the surface of the body. In contrast, the other three types are derived from the schneiderian membrane; their origins are different from the origins of the membranes that line the remainder of the respiratory tract.

Histologically, the squamous papilloma forms a localized papillomatous keratosis on a fibroepithelial stroma. Squamous papillomas usually arise from the nasal vestibule. Although papillomas that originate in the maxillary sinus have previously been reported, [4] giant squamous papillomas that cause extensive bone erosion and extend into the oral cavity are extremely rare. In our case, the patient was mentally retarded and institutionalized. This probably accounts for the late presentation of the lesion.

Squamous papillomas are benign growths that rarely cause bone erosion. Bone erosion is an important sign that should alert the clinician to the possibility of malignancy. However, benign papillomas can cause bone erosion by pressure necrosis, which might result in serious morbidity. [5] Critical areas include the bony orbital walls, the cribriform plate, the fovea ethmoidalis, and the pterygopalatine fossa. In our case, the large tumor caused a pressure necrosis of the bone and extended into the oral cavity through the defect in the socket of the decayed third molar. Unrestricted growth, even of benign papillomas, can cause death if it extends into vital structures.

Imaging studies are important in the investigation of sinonasal tumors. Meticulous interpretation is essential for accurate diagnosis and assessment of the nature and extent of the tumor. CT is helpful in evaluating soft tissue detail and its relationship to bone and the air-filled sinuses. In our case, CT clearly demonstrated the extent of the papilloma and its passage through the oroantral defect into the mouth.

Radiotherapy for squamous papilloma is ineffective and always raises the possibility of inducing malignancy. The standard treatment for nasal and paranasal papillomas is radical excision.

The primary clinical problem remains recurrence, as 25 to 75% of all nasal and paranasal papillomas are reported to recur, regardless of the histologic type. [2,5,6] Recurrence can occur years after primary resection. [2] The variable recurrence rates might be the result of an incomplete removal of the tumor, partly because of the complex anatomy of the nasal cavity and paranasal sinuses. However, with advances in endoscopic equipment and techniques, most previously inaccessible sites are now accessible.

The multiple techniques used in our case included endoscopic sinus surgery, a limited Caldwell-Luc procedure, and a transoral approach, which provided complete visualization of the tumor and allowed for its complete removal. By using this approach, we were able to avoid performing a lateral rhinotomy procedure, which leaves a facial scar.

The ability to examine the entire nasal cavity and paranasal spaces by endoscopic techniques facilitates the complete excision of the tumor, which can minimize the risk of recurrence. In view of the high recurrence rate, long-term followup, including regular endoscopic examination, is essential.

From the Division of Otorhinolaryngology, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong.

References

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