Diagnosis and differential diagnosis of lymphoepithelial carcinoma in lymph nodes: histological, cytological and electron-microscopic findings.

(1) Lymphoepithelial carcinoma, which occurs in the nasopharynx and palatine tonsils, is a special variant of squamous-cell carcinoma with a non-neoplastic lymphocytic component. (2) The morphology of lymphoepithelial carcinoma is very characteristic if not specific. Therefore, whenever lymphoepithelial carcinoma is diagnosed in a cervical lymph node, the clinician must try to find the primary tumour in the nasopharynx or tonsils, by blind biopsy if necessary. (3) The 'inflammatory' component of lymphoepithelial carcinoma is often very conspicuous. Tuberculoid lesions, with or without caseation necrosis, and marked eosinophilia and plasmacytosis are highly characteristic and help to confirm the diagnosis. (4) The 'inflammatory' component, including the lymphocytes among and around the tumour cells, is not fully understood; but it would appear that T lymphocytes are responsible for all, or most, of the cellular reactions against the tumour.