Sinonasal Inverted Papilloma Associated with Adenoid Cystic Carcinoma.

Inverted papilloma is the most common benign tumor of the paranasal sinuses with the possibility of malignant transformation. On the one hand, adenoid cystic carcinoma (ACC) is a rare malignant neoplasm that arises from the secretory glands. Sinonasal ACC accounts for 10%-25% of all head and neck ACC. This neoplasm is defined by its distinctive histologic appearance. Surgical resection, whenever possible, is the mainstay therapy. An association between inverted papilloma and malignancy is controversial. A synchronous carcinoma has been established at diagnosis in 3.3%-11% of cases, and the risk of metachronous carcinoma is <3%. We report a case of an 84-year-old female affected with sinonasal inverted papilloma associated with synchronous ACC. She had right nasal obstruction due to the rapid growth of the tumor. She was referred to our department for further workup. A frozen biopsy revealed part of the tumor as ACC. The tumor was consistent with preoperative imaging, and surgical findings also showed infiltration into the orbit. There was no consent for radical surgery with orbital exenteration and adjuvant chemoradiotherapy in consideration of her advanced age. This is the first case report of the association between sinonasal inverted papilloma and ACC within our retrieval capability.