Neuroendocrine (Merkel cell) carcinoma of the oral mucosa: report of a case with immunohistochemical study and review of the literature.

Merkel cell carcinoma (Mcc) is an uncommon and aggressive tumour with neuroendocrine features that occur predominantly in the head and neck region. The rarity of this tumour, especially when it arises in the oral mucosa, makes both early identification and standardisation of treatment difficult, particularly as regards complementary treatment. The availability of monoclonal antibodies with restricted specificity for some antigens thought to be related to neuroendocrine carcinomas, such as Merkel cell carcinoma, and ultrastructural studies offer some new leads to investigation. This has allowed, a greater number of these tumours to be discovered, thereby increasing the chances of effective management. A case of Mcc of the floor of the mouth is reported, together with the results of cytokeratin, neuron specific enolase and chromogranin immunohistochemistry.