Acellular mucin in neoplastic and non-neoplastic conditions of the lower gastrointestinal tract

Table 2 Histologic differences between low grade appendiceal mucinous neoplasm vs non-neoplastic mucin-rich conditions in the appendix

Feature	LAMN	Non-neoplastic
Extent of disease	Extensive/circumferential involvement	Focal involvement
Crypt architecture	Loss of normal crypts	Preserved crypt architecture
Lamina propria	Attenuated lamina propria	Intact lamina propria
Muscularis mucosae	Diffusely thickened	Normal thickness
Epithelial villiform proliferation	Usually present	Absent
Lymphoid aggregates (lesional)	Usually absent	Usually present
Paneth cells (lesional)	Usually absent	Usually present
Inflammatory response	Usually sparse	Frequent periappendicitis and organized abscess

LAMN: Low-grade appendiceal mucinous neoplasm.