Improved survival for stage IV sinonasal small cell neuroendocrine carcinoma treated with chemotherapy and anti-PD-L1 therapy.

Small cell carcinoma neuroendocrine type (SCCNET) is a rare tumour of the head and neck. Due to its infrequency, a paucity of data exists on optimal treatment, and the current paradigm for advanced SCCNET mirrors that of extensive small cell lung cancer. Increasingly, the treatment for extrapulmonary small cell carcinomas like SCCNET has incorporated immune checkpoint inhibitors (ICIs), although the utility of ICIs is not fully understood. We present a case of stage IVC sinonasal SCCNET in a woman in her 90s, who experienced eyelid swelling and unintentional weight loss. After diagnostic work-up, she was treated with etoposide, carboplatin and atezolizumab with a complete response to therapy. The patient had one episode of inflammatory polyarthropathy which resolved with steroids but otherwise tolerated treatment well and is now living with an overall survival of greater than 27 months. This case highlights the long-term efficacy of combination ICIs and chemotherapy in the treatment of SCCNET.