Collision Tumour of Combined Neuroendocrine and Squamous Cell Carcinoma of Nasal Cavity and Paranasal Sinus- Case Report and Review of Literature.

Background: There have been many disputes about the definition, diagnosis, therapy, and prognosis of collision tumours. Case Summary: We describe a rare patient with a collision tumour consisting of high-grade neuroendocrine carcinoma (NEC) and squamous cell carcinoma (SCC) in the right nasal cavity and paranasal sinus. She received surgery, concurrent chemoradiotherapy, and then two cycles of palliative chemotherapy. Follow-up at 26 months after diagnosis showed that this patient experienced a complete response with no signs of recurrence or metastasis. A literature review of previous 27 cases diagnosed with collision tumour of NEC and SCC in the head and neck was also undertaken. Conclusion: It is highly challenging to manage collision tumours because these are two morphologically and etiologically distinct tumours. Well-designed multimodality therapy including surgery and chemoradiotherapy might lead to a long survival in these patients.