Fine structure of nasopharyngeal carcinoma with special reference to the anaplastic type

Electron-microscopic studies of biopsy specimens obtained from 40 patients with anaplastic nasopharyngeal carcinoma revealed a variety of cytoplasmic organization in the neoplastic cells. Three modal types of tumor cells are described. The cytoplasm of type I, the most undifferentiated, contains a multitude of polyribosomes with a small amount of granular endoplasmic reticulum. Type II is distinguished by the prominence of cytoplasmic filaments, and Type III is characterized by a high density of cytoplasm with the predominance of endoplasmic reticulum and Golgi complex. The origin of the tumor cells is postulated in relation to the fine structure of the various normal epithelia of the nasopharynx. Although there are no consistent structural elements unique for nasopharyngeal carcinoma cells, loss of the polarity of tumor cells—as evidenced by lack of uniformity in the position of cytoplasmic components—and a wide range of diversity of cell size and shape in a given tumor are common features observable with the electron microscope.