Heterogeneity of colorectal adenomas, the serrated adenoma, and implications for screening and surveillance

Table 1 Comparison of SSA and TSA to TA-TVA-VA polyps

	SSA	TSA	TA-TVA-VA
Location	Right colon	Throughout, 60% left	Throughout, 60% left
Shape	Flat	Pedunculated	Pedunculated
Cytodysplasia	Minimal	Present	Present
Growth	Bottom-up	Bottom-up	Top-down
Serration	Present	Present	Absent
Basal crypt	Dilation present	Dilation absent	Dilation may be present
Horizontal crypts	Present	Absent	May be present
Branched crypts	Present	Absent	May be present
Basal serration	Present	Absent	Absent
Nuclear shape	Round or oval	Tall columnar	Tall columnar
Cytoplasm	Eosinophilic	Eosinophilic	Basophilic

SSA: Sessile serrated adenoma; TSA: Traditional serrated adenoma; TA: Tubular adenoma; TVA: Tubulovillous adenoma; VA: Villous adenoma. Adapted from Li and Burgart[11].

Table 2 Comparison of SSA polyps and HP polyps

	SSA	HP
Location	Right colon	Rectosigmoid
Shape	Flat	Pedunculated or flat
Size	> 5 mm	< 5 mm
Cytologic dysplasia	Minimal	Absent
Basal crypt dilation	Yes	No
Horizontal crypts	Yes	No
Branched crypts	Yes	No
Basal crypt serration	Yes	No
Nuclear shape	Round to oval	Flat or low columnar
Cytoplasmic eosinophilia	Prominent	Not prominent

SSA: Sessile serrated adenoma; HP: Hyperplastic polyp. Adapted from Li and Burgart[11].