However, the most prominent accumulations occur in the ileum in the form of Peyer's patches and in the appendix. Some crypts penetrate deep into the lymphoid tissue. The epithelium in contact with the lymphoid tissue is specialised to facilitate the contact of antigens with cells of the immune system. Occasionally you will see crypts extending deep into the lymphoid tissue. Compare the epithelium embedded in lymphoid tissue with that closer to the lumen of the appendix.
Goblet cells are rare or absent and the epithelium appears low columnar.