The patient went on to have a biopsy.
The section shows lymphoid tissue covered on one surface by respiratory type epithelium. Within the lymphoid tissue there are irregularly shaped islands and trabeculae of a densely hypercellular tumour.
Tumour cells have large irregularly shaped vesicular nuclei and a moderate amount of pale eosinophilic cytoplasm and are arranged in diffuse sheets. Moderate numbers of mitotic figures are noted. Intercellular bridges are discernible in some areas of the tumour. No evidence of keratinization is seen.
Tumour cells show strong immunostaining for cytokeraqtins (AE1/AE3; CAM5.2) and epithelial membrane antigen (EMA). There is also patchy weak staining for chromogranin. No staining for EBV-LMP is seen. The features of poorly differentiated non-keratinizing squamous cell carcinoma.
Final diagnosis: Poorly differentiated squamous cell carcinoma.