RESUMO
INTRODUCTION: Neuroendocrine carcinoma is a rare form of cancer originating from neuroendocrine cells, with the lungs being the most common site of occurrence. These tumors have the potential to metastasize to the head and neck region. CASE REPORT: A 57-year-old man, with a smoking history of 74 pack-years, presented with complaints of hoarseness, dry cough, dysphagia, and significant weight loss over a two-month period. During oral examination, a submucosal nodule in the left palatine tonsil was discovered. Histological analysis confirmed a poorly differentiated tumor consisting of large cells with nuclear pleomorphism and abundant cytoplasm. The tumor tested positive for CD56, chromogranin, synaptophysin, and EMA. Further imaging revealed a substantial endobronchial lesion in the upper segment of the left lower lobe. Biopsy results from this lesion were morphologically and immunohistochemically consistent with those from the oral lesion. A diagnosis of metastatic large-cell neuroendocrine carcinoma originating from the lung and involving the oral mucosa was established. CONCLUSION: This case highlights the metastatic potential of pulmonary neuroendocrine carcinoma and its occurrence in atypical dissemination sites. Additionally, our findings underscore the importance of early detection of oral metastases to ensure accurate diagnosis and expedite appropriate treatment.