Introduction

Inverted papillomas (IP) are benign epithelial growths in the nasal cavity and the paranasal sinuses with a high tendency to recur. Despite their benign nature, IP"s may grow locally invasive and turn malignant in 12% of cases. A recently described distinct histological entity of squamous cell carcinoma is defined by the presence of a DEK:AFF2 fusion. The case highlights the significance of investigating recurrent IP cases for this specific gene fusion.

Method

A 46 year old woman experienced right sided nasal congestion, tear duct discomfort and swelling in the medial canthus. Multiple endonasal endoscopic excisions were performed for recurrent inverted papilloma in 2019, 2020, 2021. Extensive diagnostic imaging was utilized to assess disease extent. The histopathological analysis during the fifth surgery revealed an unexpected diagnosis.

Results

Upon histological testing of the resected tumor material, a keratinizing squamous cell carcinoma was identified( cT4a cN0 M0). Genetic testing revealed a DEK-AFF2 Fusion. The patient underwent orbit-sparing transfacial re-resection via a Killian"s incision followed by adjuvant hyperfractionated chemoradiation with weekly cisplatin.

Discussion

DEK:AFF2 fusion squamous cell carcinomas are exceptionally rare but may be under diagnosed due to its only recent description. Typically, this new entity has been firmly diagnosed as recurrent inverted papilloma. This reclassification leads to speculation that this diagnosis was potentially present in the previous samples. The literature is inconsistent with regards to the biological behavior. We treated the patient in line with recurrent squamous cell carcinoma. This case warrants molecular investigation in cases of recurrent or atypical inverted papillomas

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