Mucosal Prolapse / Cloacogenic Polyp
Differential Diagnosis
- Peutz Jeghers type hamartomatous polyp
- Adenoma
- Juvenile polyp
- Cowden Disease
- Inflammatory/reactive polyp
- Perineurioma
- Invasive adenocarcinoma
- Crohn disease
- Ulcerative colitis
| Mucosal Prolapse / Cloacogenic Polyp | Peutz-Jeghers Polyp |
| Usually solitary polyp | Usually multiple |
| Smooth muscle surrounds individual crypts | Prominent arborizing smooth muscle bundles surround groups of crypts |
| Polyps rare in small intestine | Most polyps in small intestine |
| Not associated with oral pigmentation | Associated with oral pigmentation |
| Mucosal Prolapse / Cloacogenic Polyp | Colorectal Adenoma |
| Nuclear atypia most prominent deep in the lesion with surface maturation | Nuclear atypia involves surface of polyp |
| Nuclei usually enlarged but round and not stratified and not densely packed | Nuclei elongated, hyperchromatic, densely packed and frequently stratified |
| Apoptosis not prominent | Prominent apoptosis |
| Mucosal Prolapse / Cloacogenic Polyp | Sporadic Juvenile Polyp |
| Surface erosions with granulation tissue frequent | Surface erosions infrequent |
| Irregular glands with scattered dilation | Prominent, regularly dilated glands |
| Smooth muscle extension into lamina propria of polyps | No smooth muscle in lamina propria of polyps |
| Restricted to rectum (rarely in sigmoid) | May involve any part of colorectum |
| Mucosal Prolapse / Cloacogenic Polyp | Cowden Disease, Colorectal Polyp |
| Surface erosions with granulation tissue frequent | Surface erosions infrequent |
| Irregular glands with scattered dilation | Prominent, regularly dilated glands |
| Smooth muscle extension into lamina propria of polyps | No smooth muscle in lamina propria of polyps |
| Restricted to rectum (rarely in sigmoid) | May involve any part of colorectum |
| No associated lesions | Most have facial and oral papillomas, fibromas and skin tumors, see description LINK |
| No genetic abnormality | PTEN mutations in 80% |
| Mucosal Prolapse / Cloacogenic Polyp | Reactive / Inflammatory Polyp |
| Smooth muscle extension into lamina propria of polyps | No smooth muscle in lamina propria of polyps |
| Usually localized to rectum | Usually multiple, may involve any inflamed area |
| Not associated with inflammatory bowel disease | Usually associated with ulcerative colitis but may be sporadic |
| Mucosal Prolapse / Cloacogenic Polyp | GI Perineurioma |
| Fibrovascular stroma | Lacks vascularity |
| Inflammatory infiltrate | Inflammation infrequent |
| Prominent gland component | Mostly a spindled stromal lesion, crypts pushed aside |
| Villiform eroded surface | Surface intact and normal |
| Smooth muscle extends into lamina propria around crypts | Lamina propria spindled lesion is smooth muscle actin negative and positive for perineurial markers |
| Mucosal Prolapse / Cloacogenic Polyp (Localized Colitis Cystica Profunda) | Invasive Colorectal Adenocarcinoma |
| No surface carcinoma component | Surface component usually present |
| No high grade nuclear atypia | High grade nuclear atypia usually present |
| No cribriform glands or complex architecture | Complex architecture with cribriform glands frequent |
| No desmoplastic stromal response | Desmoplastic stromal response |
| Lamina propria may accompany displaced glands | No lamina propria accompanying invasive glands |
| Mean age 35 years | Occurs in older patients |
| Mucosal Prolapse / Cloacogenic Polyp (Solitary Rectal Ulcer) | Crohn Disease |
| Shallow ulceration | Deep ulcers and fissures |
| Restricted to rectum (rarely in sigmoid) | May involve any part of GI tract |
| Mucosal Prolapse / Cloacogenic Polyp (Solitary Rectal Ulcer) | Ulcerative Colitis |
| Usually a localized lesion | Usually a diffuse lesion |
| Adjacent, intervening mucosa normal | Adjacent, intervening mucosa inflamed |
| Restricted to rectum (rarely in sigmoid) | May involve longer segments of colon |
