Table 2. Histological key features of microscopic colitis (collagenous colitis and lymphocytic colitis) and MCi (collagenous colitis incomplete and lymphocytic colitis incomplete).

Clinical groups	Morphology subgroups	Increased mononuclear inflammation of lamina propria	Thickness of collagenous band	Number of IELs
MC	CC	Moderately increased	>10 ìm	Normal/slightly increased
	LC	Moderately increased	Normal/slightly increased	>20 IELs/100 cells
MCi	CCi and LCi	Slightly increased	>5 and <10 ìm	>10 IELs and <20 IELs

MC, microscopic colitis; CC, collagenous colitis; LC, lymphocytic colitis; MCi, microscopic colitis incomplete; CCi, collagenous colitis incomplete; LCi, lymphocytic colitis incomplete; IELs, intraepithelial lymphocytes.