Hyperplastic Polyp / Mucosal Hyperplasia of the Appendix
Definition
- Serrated mucosal proliferations in the appendix lacking both architectural and cytological dysplasia
Diagnostic Criteria
- Mucosal hyperplasia, hyperplastic polyp and sessile serrated polyp have quite similar appearances in the appendix
- Architectural distortion due to obstructive changes may make the distinctions difficult
- Criteria for their distinction have not been tested for reproducibility in the appendix
- Architectural criteria for separation of sessile serrated polyp from hyperplastic lesions are based on those used in the colorectum
- Appearance is similar to hyperplastic polyp of the colorectum
- Upper (luminal) portion of polyp has a “saw tooth” appearance
- Nuclei are small, regular, round and basal
- Best evaluated on or near the luminal surface
- Bases of crypts show proliferative changes
- It is not clear that hyperplastic polyps and mucosal hyperplasia can or need to be separated in the appendix
- Polypoid vs. sessile distinction has been proposed
- This is not reliably made in the appendix
- Both are common incidental lesions
- Both are uncommonly associated with appendiceal dilation
- Neither has been shown to be a precursor of carcinoma or be associated with pseudomyxoma peritonei
- Polypoid vs. sessile distinction has been proposed
- The entire appendix should be examined microscopically
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting/updates : 10/21/10