Changes in the lamina propria :
I. Changes in Cellularity :
superficial : Cellular infiltrate confined to the superficial and middle
third of lamina propria (eg. Infective colitis).
transmucosal : Increase in cellular infiltrate throughout the lamina
in inflammatory cells in a background of normal mucosa (Example: Crohn's
inflammation characterized by variation in intensity of inflammation from
one part of mucosa to another (Example.
Amoebiasis ; foreign
body reaction and wide variety of other conditions).
neutrophils in the lamina propria is an important marker of active
inflammation. Polymorph inflammation may be graded on numbers per crypt or
per millimeter in lamina propria.
In florid acute inflammation neutrophil
polymorphs are present in large numbers in the lamina propria, within
epithelium and in the lumen of crypts forming crypt abscess. (Example:
phases of ulcerative colitis,
Amoebiasis, acute infective proctocolitis).
Plasma cells are non-specific marker of inflammation.
A heavy infiltrate of
plasma cells may predominate throughout the lamina propria in case of
chronic ulcerative colitis.
Lymphocytes are of
diagnostic significans when present in large numbers.
In follicular proctitis there is hyperplasia of lymphoid follicles in the lamina propria
(Example: Ulcerative colitis).
Irregularly arranged dense aggregates of lymphocytes adjacent to bases of crypts with
extension into the submucosa is seen in Crohn's disease.
Lymphoma should be ruled
out when there is an increase in intraepithelial lymphocytes.
Eosinophils may be
present in a wide range of conditions.
schistosomiasis ; some
cases of ulcerative colitis; as systemic reaction in atopic disease like
asthma ; in acute phase of irradiation proctitis etc.)
PAS positive histiocytes are noted in
whipple's disease ; melanosis coli;
In xanthoma lipid containing histiocytes are present
in the superficial lamina propria.
containing macrophages are present in melanosis coli.
giant cells: A granuloma consists of at least five epithelioid cells with
or without accompanying multinucleated giant cells.
This is a specific
marker of Crohn's disease (a submucosal granuloma is diagnostic).
formed granulomas are identified in the following disease conditions:
Mycobacterium avium intracellular
infection in patients with AIDS.
5. Around ova in chronic
6. Fungal infection
7. Foreign body reaction
8. Diversion colitis. Giant
cells may be present in response to crypt destruction or in
response to foreign material (faecal material or barium).
histiocytic reaction in response to crypt rupture may be present in
infective colitis or
ulcerative colitis. Crohn's should not be diagnosed
based only on the presence of giant cells or ill defined collection of
Other changes in the lamina propria:
Pseudolipomatosis of the
large intestinal mucosa is characterized by small gas containing vacuoles
in the lamina propria resembling mature adipose tissue.
probably appear following prolonged lymphocytic infiltration.
(Example: Longstanding ulcerative
be present in the lamina propria and these include
herpes simplex .
II. Changes in the
matrix of the lamina propria:
a) Fibrosis of lamina
(i) Solitary ulcer syndrome.
(ii) Dysplastic glandular epithelium in a
desmoplastic stroma is highly indicative of adenocarcinoma.
b) Presence of muscle fibres in the lamina propria:
(i) Solitary ulcer syndrome (mucosal prolapse)
(ii) Polyps- eg.
Inflammatory 'cap' polyp and Peutz Jegher's polyp.
c) Hyalinization of the
lamina propria : In
chronic radiation damage.
d) Haemorrhage in the
lamina propria :
could be an artefact.
(ii) Useful sign in acute ischaemic colitis.
2. Changes in the muscularis mucosae and submucosa:
stricture formation, fibrosis, splaying of fibres :
of muscularis mucosae occurs near an obstructive lesion (Example: Carcinoma or Hirschsprung's disease) and in chronic ulcerative
stricture (common complication of Crohn's disease) is histologically
characterized by an increase in smooth muscle cells in the muscularis
mucosae and presence of large amounts of collagen (Type V and III ), laminin and tenasin.
Splaying of muscle
fibres into the lamina propria is noted in 'mucosal prolapse syndrome'.
II Submucosa -
- Widening of submucosa by edema is a sign of active disease (eg. Crohn's disease).
Numerous lymphoid aggregates and nodules are present in the submucosa in
Disproportionate inflammation is characterized by inflammatory infiltrate in the submucosa which is denser than the
inflammation in the overlying mucosa (Example: Crohn's).
Inflammation in the submucosa with almost normal mucosa may be present
adjacent to a diverticulum or abscess, in a deep flask-shaped ulcer of amoebiasis, at the edge of a fissure and in tuberculosis.
Irregular hypertrophy and hyperplasia of the nerve fibres (neuromatous lesions) and
unusually prominent submucosal nerve ganglia may be present Crohn's
- Inflammatory cell infiltration of blood vessels and obliterative lesions
have been noted in the submucosa in Crohn's disease.
vasculitis and lymphangiectasia in the submucosa are common findings in
Rectal biopsy is an useful diagnostic tool in the
detection of systemic vasculitis and amyloid.
Blood vessels in the submucosa should also be examined in suspected cases of angiodysplasia.
from carcinoma by the presence of lamina propria around the glands
together with haemosiderin laden
Interpretation of Large Intestinal Biopsies
Assessment of the
Intestinal abnormalities - lumen, surface epithelium and the subepithelial
Assessment of the
architecture and epithelium
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ed. Philadelphia,Lippincott, Williams & Wilkins,1999 ; 1344-1411.
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abnormalities : Diagnostic signposts. In biopsy pathology in colorectal
disease.London: Chapman and Hall,1987; 261-2.
variability in the histopathological reporting of abnormal rectal biopsy
specimens. J Clin Pathol. 1994 ;47:48-52.
of large intestinal mucosal biopsy specimens. Hum Pathol 1994; 25: 1150-9