UNASSIGNED: The inverted and oncocytic subtypes of sinonasal Schneiderian papillomas are benign tumors with possible rare malignant transformation and are typically managed with complete surgical resection and close follow-up. While computed tomography (CT) and magnetic resonance imaging (MRI) are mainstays in preoperative evaluation of bony invasion and soft tissue extension of the lesion, their imaging characteristics by 18F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) is less well characterized.
UNASSIGNED: To describe the clinical presentation and management of a PET positive sinonasal lesion. To conduct a literature review of FDG uptake in benign sinonasal papillomas.
UNASSIGNED: Case report (n = 1) and literature review of similar cases (n = 32).
UNASSIGNED: We report the case of a 69-year-old man presenting with an isolated left maxillary sinus mass with avid FDG uptake, discovered on PET/CT imaging. An endoscopic left maxillary mega-antrostomy provided successful definitive treatment for final pathologic diagnosis of oncocytic papilloma. Literature review of cases of sinonasal papillomas with avid FDG uptake found that oncocytic papillomas, on average, exhibit greater uptake than inverted papillomas and both may be mistaken as malignancies on PET.
UNASSIGNED: While PET imaging demonstrating avid FDG uptake is associated with an increased risk of malignancy, it does not rule out the possibility of a benign sinonasal papilloma nor other benign inflammatory lesions. Particularly, oncocytic papillomas may have very high FDG uptake and mimic malignant lesions.

Papillomas are uncommon tumors of the sinonasal tract histologically derived from the Schneiderian membrane. Three distinctive variants are described, the exophytic, the inverting and the oncocytic types. On physical examination, their appearance varies from exophytic-fungiform seen in the exophytic variant, to polypoid-papillary in both the inverting and oncocytic variant. The presence of an asymptomatic mass or epistaxis and unilateral nasal obstruction are the typical presenting symptoms. Clinically they tend to recur and, although benign, they may erode the bone laminas by pressure, especially the inverting type, causing proptosis and other co-morbidities. Malignant transformation is seen both synchronously, on a pre-existing papilloma, and metachronously after several recurrences of papilloma. Schneiderian papillomas are at a date a topic of controversy regarding their etiology, pathogenesis and biological behavior. Furthermore, histologic criteria to assess dysplasia and malignant transformation are ill-defined. The present study aims to comparatively review the histologic types of papillomas, their etiology, the currently available criteria for malignant transformation, their treatment and prognosis.

OBJECTIVE: To evaluate the clinical presentation, treatment outcome and follow-up of all patients managed with sinonasal papillomas (SP), at a tertiary private otorhinolaryngology centre in Caracas (Venezuela).
METHODS: We reviewed 94 patients with SP that were treated at our otolaryngology center, from July 1st 1993 to June 31st 2015. The demographic data, clinical features, radiological findings, anatomical origin, disease extension into the adjacent structures, surgical approaches performed, histopathology outcomes, recurrent risk, malignant transformation rate and coadjuvant therapies were assessed.
RESULTS: Sixty-five patients (69.1%) were male and 29 (30.9%) female with an average age of 44.5 years (range 9-80 years). All patients underwent endoscopic sinus surgery. The most commont histologic subtypes of SP were inverted papilloma (58 patients; 61.7%), fungiform papilloma (35 patients; 37.2%) and oncocytic papilloma (one patient; 1.1%). SP was associated in 2 patients with undifferentiated squamous cell carcinoma. Twelve patients (12.8%) had disease with extension beyond the sinus without associated malignancy. All these patients received adjuvant treatment with advanced techniques of radiotherapy. The mean duration of the follow-up period was 9 years and 2 months. Eighteen patients (19.1%) had recurrent disease during the entire course of follow-up.
CONCLUSIONS: Complete endoscopic surgical removal of SP is the treatment of choice. In less endoscopically accessible tumours, with peripheral extension or incompletely resected, Intensity Modulated Radiotherapy and Volumetric Modulated Arc Therapy may be indicated. Timely post-operative endoscopic follow-up with biopsy of suspected lesions is important for early detection of recurrences and associated malignancy.