Colorectal Adenoma with Benign Misplacement of Glands / Pseudoinvasion
Supplemental Studies
Immunohistology
- Collagen type IV
- Stains normal basement membrane strongly
- Entrapped nests show strong, continuous staining of surrounding basement membrane
- Invasive carcinoma shows only weak, discontinuous staining
- Loss of staining reported to be 100% specific, 96% sensitive
- E cadherin
- Stains cell membranes of normal and adenomatous epithelium strongly
- Carcinoma shows markedly decreased intensity
- Loss of staining reported to be 100% specific, 65% sensitive
- p53
- Usually scattered nuclear staining in adenomas
- Usually extensive nuclear staining in carcinoma
- Reported to be 96% specific and 61% sensitive
- Data from Yantiss 2002
- Special stains are not generally required for diagnosis
