Combined Neuroendocrine and Squamous Cell Carcinoma of the Sinonasal Tract: A Morphologic and Immunohistochemical Analysis and Review of Literature.

Shweta Agarwal, Annemieke van Zante, Michaela L Granados

Head and neck pathology 2022 Dec

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Sinonasal malignancies constitute 3% of head and neck cancers, with squamous cell carcinoma (SCC) the most common histology. Neuroendocrine carcinomas (NEC) are rare, with a subset showing neuroendocrine carcinoma and a non-neuroendocrine component. The pathogenesis of these combined tumors is largely unknown, and TP53 driver mutations may play a role. A database search for combined NEC was performed across two institutions (UNM and UCSF) spanning 15 years. Excluding NUT midline carcinoma, 3 cases met inclusion criteria. All were morphologically NEC + SCC and underwent a comprehensive immunohistochemical evaluation. Tumors demonstrated two components histologically: moderately to poorly differentiated SCC and high-grade NEC. Divergent differentiation was confirmed with lineage-specific markers. Only one patient received neoadjuvant chemotherapy prior to surgery, with a remarkable response (a marked decrease in the size of the primary lesion and resolution of liver metastases). Immunohistochemical staining for p53 was increased in 2 of 3 cases (both components), suggesting a role in the carcinogenesis of these tumors. Aberrant expression of beta-catenin was not identified. One case tested positive for p16, which can be seen in high grade NECs due to inactivation of Rb gene. Additionally, both cases with a small cell NEC component expressed PD-L1, suggesting that immunotherapy may be an effective treatment. Findings in this study support the role of p53 mutation in a subset of combined NEC + SCC of the sinonasal tract. Recognition of this rare entity is essential for optimal management of these aggressive neoplasms. © 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.

Citation

Shweta Agarwal, Annemieke van Zante, Michaela L Granados. Combined Neuroendocrine and Squamous Cell Carcinoma of the Sinonasal Tract: A Morphologic and Immunohistochemical Analysis and Review of Literature. Head and neck pathology. 2022 Dec;16(4):1019-1033