Nasopharyngeal carcinoma

Undifferentiated carcinoma (lymphoepithelioma) of the nasopharynx. Tumor cells (left panel) are large with vesicular nuclei and prominent nucleoli and are dispersed in an intense background of mature lymphocytes. Cytokeratin immunostains highlight many more tumor cells than are apparent in the routine histology (right panel). These are Epstein-Barr virus associated tumors.