Surgical Pathology Criteria

Hyperplastic Polyp of the Colon and Rectum

Differential Diagnosis

Hyperplastic Polyp Tubular Adenoma
Lacks cytologic dysplasia Requires cytologic dysplasia
Proliferative zone restricted to base Proliferative zone starts at the surface
Gland lining cells mature at the surface No surface maturation
Deep proliferative zone of HP can resemble TA; the surface must be examined to make the distinction in many cases

 

Hyperplastic Polyp Sessile Serrated Polyp / Adenoma
≥90% of bases of crypts straight, regular, narrow, frequently pointed, no dilated flattened bases 1 to 3 crypts required with basal dilation and flattening, bases boot or inverted T shaped, <90% of bases are narrow
Proliferative zone reliably restricted to base Bases contain mature mucous cells
Serrations and CK20+ maturation limited to luminal 2/3 of crypt Serrations and CK20+ patches of maturation can be seen at all levels
Predominantly left sided and small Predominantly right sided and frequently ≥1 cm
Polyps with mixed or intermediate features are designated indeterminate (e.g. between 50-90% narrow crypts and/or <3 flat crypt bases)

 

Traditional Serrated Adenoma Hyperplastic Polyp
Cytologic dysplasia throughout Lacks cytologic dysplasia
Typically complex architecture Crypts are vertically arranged and not complex
Multiple ectopic crypt foci (short disoriented crypts not reaching the muscularis mucosae) Crypts each span from lumen to muscularis mucosae

 

Sporadic Juvenile Polyp Hyperplastic Polyp
Prominent cystically dilated glands Cystic dilation not prominent
Irregular glands Glands are vertically arranged and not complex

 

Hyperplastic Polyp with Mucosal Entrapment (Inverted Hyperplastic Polyp) Mucosal Prolapse / Cloacogenic Polyp
Lacks surface erosion Surface erosions with granulation tissue frequent
No smooth muscle extension into lamina propria Smooth muscle extension into lamina propria of polyps
Lacks regenerative change May have regenerative change in epithelium of polyp

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