Fig. 2.

Carcinoma in situ with ‘nonkeratinizing’ histologic features compared to conventional severe dysplasia. a Low power (×100) hematoxylin and eosin stained section showing extensive ‘nonkeratinizing’ carcinoma in situ with a dense lymphoplasmocytic inflammatory infiltrate in the submucosa. b High power (×400) hematoxylin and eosin stained section of ‘nonkeratinizing’ carcinoma in situ showing complete loss of maturation with replacement of the epithelium by dysplastic cells that have oval to spindled, hyperchromatic nuclei and indistinct cell borders. Mitotic activity is brisk and apoptotic debris is present. c Conventional severe dysplasia showing polygonal cells with pleomorphic nuclei, abundant pink cytoplasm and distinct cell borders (×200)