features in a Normal Large Intestinal Biopsy:
There is increase
in thickness of the mucosa from the caecum (500 micrometer) to the rectum
Crypts are aligned
parallel to the crypt bases. Crypts are straight and narrow and mostly
unbranched separated by a thin rim of lamina propria.
The distance between the
crypts and the internal diameter of the crypts are constant.
in crypt architecture, intercryptal spacing and occasional crypt branching
may occur in normal biopsies.
Crypts are deeper
in the rectum and sigmoid colon than in the proximal part of the colon.
absorptive (tall columnar), goblet and endocrine cells.
Ratio of the
number of tall columnar cells to goblet cells is 4:1.
Paneth cells are
usually present in the caecum & proximal colon (usually confined to the
Presence of Paneth
cells more distally indicates metaplastic change seen in chronic
zone in the base of the crypt is composed of low cuboidal stem cells.
cells overlying lymphoid follicles are more cuboidal and compactly
arranged rather than columnar cells elsewhere (this should not be mistaken
for dysplastic cells in ulcerative colitis).
connective tissue which appears highly cellular due to the presence of
chronic inflammatory cells in the superficial part of the lamina propria.
plasma cells are present together with scattered lymphocytes (mostly
in the deeper part and separation of crypt bases from muscularis mucosae
by a band of plasma cells and lymphocytes is indicative of chronic
inflammatory bowel disease.
Occasional neutrophils are present in the lamina propria of normal colonic biopsies.
Neutrophils in the
surface and crypt epithelium is indicative of a pathological process.
of B-lymphocytes are present in colonic mucosa and may extend through
muscularis mucosae into submucosa.
At these points
mucosal crypts extend into the mucosa forming lymphoid-glandular complexes
(should not be mistaken for a pathological process).
smooth muscle layer (inner circular and outer longitudinal layer).
There is loose
connective tissue with collagen and elastic fibres.
Meissner's plexus of
autonomic nerve fibres with ganglion cells are present.
examination of this layer is necessary in Hirschsprung's disease.