Undifferentiated carcinoma of the nasopharynx: a light and electron microscopical study

Light microscopical study of 29 cases of undifferentiated carcinoma of the nasopharynx showed evidence or origin of the tumour cells from overlying epithelium in 10 cases. In all cases the tumour cells had a distinctive cellular appearance of 'empty' chromatin deficient nuclei, prominent nucleoli and indefinite cytoplasmic margins. Electron microscopy indicated desmosomes and poorly defined tonofilaments in addition to the above cytoplasmic features. Undifferentiated carcinoma of the nasopharynx shows characteristic light and electron microscopic features which indicate that the tumour cells take origin from squamous epithelium, but are of an extreme degree of dedifferentiation.