Chapter17: INTESTINES:Tumors of the Anal Canal

Question 1

The anal canal can be divided into thirds.

Answer 1

• The upper zone is lined by columnar rectal epithelium;
• the middle third by transitional epithelium; and
• the lower third by stratified squamous epithelium.

UC

MT

LS

Question 2

Answer 2

FIGURE 17-54 Anal tumors.

• A, This squamous anal transition zone tumor forms nests with central necrosis. The adjacent rectal mucosa is intact.
• B, This basaloid anal transition zone tumor is composed of hyperchromatic cells that resemble the basal layer of normal squamous mucosa.
• C, Condyloma accuminatum with verrucous architecture.