Abstract
Neuroendocrine tumours (NETs) primarily affect the lungs and larynx. Primary neuroendocrine carcinomas (NECs) rarely occur in the oral cavity. The classification of these tumours is ambiguous; however, the literature acknowledges their aggressiveness. Merkel cell carcinoma (MCC) is rare and more common in the skin but could occur intraorally. MCC and NECs are aggressive neoplasms and recommend intensive treatment. In this case report, a 22-year-old female presented with an ulceroinfiltrative lesion in the left buccal mucosa of the cheek, which was diagnosed as primary NEC in the oral cavity. This patient underwent wide local lesion excision of oral cavity mass, ipsilateral selective neck node dissection of levels 1-4 and postoperative chemotherapy. This aggressive tumour type requires large local excisions with margins like Merkel cell skin carcinomas. To our knowledge, this is the youngest oral cavity primary neuroendocrine cancer patient to date in the literature.