multifocal inverting papilloma of the sinonasal cavity and temporal bone

Introduction: Inverting papillomas (IPs) represent the most common benign neoplasm of the sinonasal cavity and are known for local invasion, proclivity for recurrence, and risk of malignant transformation. IP of the temporal bone (TBIP) is exceptionally rare, with 32 reported cases. We present a new case of multifocal IP of the sinonasal cavity and temporal bone. Methods: Case report and review of the literature. Results: A 45-year-old man presented with a left sided biopsy proven IP and associated left sided hearing loss. Imaging demonstrated a left sided nasal mass and a separate non-contiguous soft tissue mass filling the left middle ear without involvement of the eustachian tube. He underwent an endonasal endoscopic gross total resection of the sinonasal lesion and biopsy of the middle ear mass with pathology showing IP. He subsequently underwent a left sided transtemporal resection of the TBIP. Review of the literature, revealed 32 TBIP cases, with 59% having history of associated sinonasal IP and 41% with isolated temporal bone disease. Over half of the patients demonstrated recurrence. In comparison to patients with history of sinonasal IP, isolated TBIP occurred in younger patients, was more common in females, and had less association with HPV and malignant transformation. Conclusion: TBIP is extraordinarily rare and usually presents with a history of sinonasal IP. Isolated TBIP may be a distinctly different disease process. Disease recurrence is common and risk of malignant transformation is present, so aggressive initial surgical treatment with gross total resection is advocated.