ABSTRACT
The most important principle to remember is that carcinoma, as defined in Chapter 14, can be said to be present when the neoplastic epithelium has extended into or through the muscularis mucosae (Morson and Sobin, 1976). To observe this in a biopsy requires an adequate sample and good orientation. These are not always achieved and, in practice, the features requiring scrutiny are:
1. The glandular epithelium and the degree of dysplasia.
