GASTROINTESTINAL PATHOLOGY

CHAPTER 14 GASTROINTESTINAL PATHOLOGY



Esophagus
Histological variants of normal esophagus

Esophageal atresia and tracheo-esophageal fistula

Esophageal stenosis and webs

Duplication cysts

Esophageal diverticulum

Achalasia

Gastro-esophageal reflux disease

Columnar epithelial lined esophagus

Eosinophilic esophagitis

Infective esophagitis

Crohn’s disease of the esophagus

Chemical and drug-induced esophagitis

Stomach
Gastritis

Hypertrophic pyloric stenosis

Gastric volvulus

Graft-versus-host disease

Gastric tumors

Spontaneous perforation of the GI tract

Small intestine
Intestinal atresia

Meckel’s diverticulum and related vitellointestinal remnants

Meckel’s diverticulum

Omphalomesenteric cysts and sinus

Duplication cysts

Intussusception

Volvulus

Meconium ileus

Crohn’s disease

Intestinal infections

Neonatal necrotizing enterocolitis

Spontaneous perforation of the small intestine

Food allergy

Primary intestinal failure / neonatal-infantile enteropathies

Celiac disease (gluten sensitive enteropathy)

Tufting enteropathy

Infantile autoimmune enteropathy

Microvillous inclusion disease

Intestinal lymphangiectasia

Dissacharidase assessment of jejunal specimens

Intractable enterocolitis of infancy

Abetalipoproteinemia

Pathology of intestinal transplantation

Short bowel syndrome

Intestinal graft-versus-host disease

Gastrointestinal neuromuscular / motility diseases
Achalasia of esophagus

Hypertrophic pyloric stenosis

Hirschsprung’s disease

Hirschsprung’s-associated enterocolitis

Intestinal ganglioneuromatosis

Hypoganglionosis

Idiopathic myenteric ganglionitis

Internal anal sphincter achalasia

Megacystis microcolon intestinal hypoperistalsis syndrome

Chronic intestinal pseudo-obstruction

Idiopathic slow transit constipation

Role of interstitial cells of Cajal in intestinal motility disorders

Miscellaneous

Colon
Chronic inflammatory bowel disease

Fibrosing colonopathy

Melanosis coli

Miscellaneous GI specimens
Hernia sac

Exomphalos sac

Anorectal anomalies

Currarino triad

Tailgut cyst

Vermiform appendix
Acute appendicitis

The gut and immunodeficiency
Selective IgA deficiency

X-linked (Bruton) agammaglobulinemia

Common variable immune deficiency

Severe combined immunodeficiency

Wiskott–Aldrich syndrome

Chronic granulomatous disease

Chronic mucocutaneous candidiasis

Leucocyte adhesion deficiency

Ataxia telangiectasia

Schwachman–Diamond syndrome

Pancreas
Persistent hyperinsulinemic hypoglycemia of infancy

Insulinoma

Tumors
Familial adenomatous polyposis

Hereditary non-polyposis colorectal cancer

Juvenile polyps

Juvenile polyposis

Peutz–Jeghers syndrome

Cowden syndrome (PTEN hamartoma tumor syndrome)

Other intestinal polyps

Gastric polyps

Burkitt’s lymphoma

Mesenchymal gastrointestinal tumors

Appendiceal carcinoid

Pancreatoblastoma

Pancreatic solid-pseudopapillary neoplasm



INTRODUCTION



• Specimens from the gastrointestinal tract comprise a significant proportion of the workload of many pediatric surgical pathology departments
image number is increasing with advances in endoscopic techniques

• Complexity of GI disease is increasing since
image newer forms of treatment becoming available which may alter classical histological appearances
– such as monoclonal anti-inflammatory antibodies

image newer forms of treatment for non-GI disease may also cause changes in the GI tract

image GI involvement in diseases previously not suspected to have GI pathology
– such as enteropathy in Shwachmann–Diamond syndrome

• Entities provided in this chapter are primarily those seen with reasonable frequency as surgical pathology specimens
image most organized by main site of involvement
– some entities may affect multiple sites but are documented according to the usual site of disease


ESOPHAGUS



HISTOLOGICAL VARIANTS OF NORMAL ESOPHAGUS



• Normally lined by non-keratinizing squamous epithelium but several normal variants may occur
image islands of ciliated columnar epithelium (Fig 14.1)
– up to 16 weeks’ gestation the normal esophagus has ciliated lining

image heterotopic gastric mucosa in postcricoid area
– visible as oval pink patches endoscopically

image sebaceous glands beneath squamous epithelium

image

Fig 14.1 Photomicrograph of esophageal biopsy. The epithelium is hyperplastic and shows ciliated columnar epithelial cells. Such cells may occasionally be seen in normal esophagus or in association with developmental abnormalities.



ESOPHAGEAL ATRESIA AND TRACHEO-ESOPHAGEAL FISTULA



• 1 : 3000–5000

• Associated maternal polyhydramnios (50%)

• Around half of cases preterm with associated abnormalities
image cardiac defects

image imperforate anus

image duodenal atresia

• Associations
image VATER
– vertebral defects

– anal atresia

– tracheo-esophageal fistula

– radial and renal abnormalities

image VACTERL
– vertebral defects

– anal atresia

– cardiac defects

– tracheo-esophageal fistula

– renal abnormalities

– limb defects

image CHARGE
– coloboma

– heart defects

– choanal atresia

– retarded growth

– genital abnormalities

– ear anomalies

• Commonest variants are
image proximal esophageal atresia with distal tracheo-esophageal fistula (85%)
– esophagus as blind ending pouch short distance from cricoid

– gap of 1–2cm

– fistula usually takes origin from the carina posteriorly

image pure EA without fistula (10%)
– gap wider than the above

– high incidence of trisomy 21

image ‘H’ type (5%)
– usually do not have associated abnormalities

– diagnosis usually later


Histopathological features (Dutta, Mathur, Bhatnagar 2000)



• Unusual to get surgical specimen

• When submitted tissue comprises elements of tracheal and esophageal wall in variable combinations according to case (Figs 14.2, 14.3)

image

Fig 14.2 One-day-old girl with esophageal atresia and tracheo-esophageal fistula. The specimen is the tip of the proximal esophageal pouch. Photomicrograph of the specimen demonstrating the pouch comprising the usual elements of esophageal wall. The mucosa shows some ciliated epithelium. Unusually, no striated muscle was present in the muscular coat.


image

Fig 14.3 One-year-old girl with previous EA repair. Stricture below anastomosis excised. Photomicrograph of the excised piece of esophagus with thickened and disorganized muscle coat and containing bronchial type glands extending deeply into the muscle coat.



ESOPHAGEAL STENOSIS AND WEBS



• Rare

• True congenital lesions akin to esophageal atresia

• May be associated with TEF

• Webs commoner in mid esophagus

• Stenosis commoner in lower esophagus


Histopathological features



• Stenosis
image usually shows tracheobronchial remnants in wall of esophagus

image may have cartilaginous rings

• Webs
image mucosal and submucosal tissue only


DUPLICATION CYSTS



• Developmental defects
image can affect any site in the GI tract from esophagus to rectum

• Variable size

• Tubal or spherical

• Mass effects or incidental

• In thorax
image may be associated with vertebral defects

image may communicate with spinal canal
– neuroenteric cyst

• Present with
image respiratory distress

image feeding difficulty


Histopathological features



• Two layered muscularis propria

• Variable gastrointestinal mucosal lining type (Figs 14.4, 14.5)

image

Fig 14.4 Nine-month-old boy. Antenatal diagnosis of thoracic cyst. Posterior mediastinal cyst (3.5 × 3 × 2.5 cm) attached to wall of esophagus beneath the right vagus nerve with a fibrous attachment to the vertebral body. It contained clear fluid. Photomicrograph of the cyst wall demonstrating double muscle layer lined by simple gastric cardiac type mucosa. Focally there was ulceration.


image

Fig 14.5 Three-year-old boy with an incidental finding of a para-esophageal cyst (1.7 × 1 × 1 cm) during fundoplication. Photomicrograph of the cyst wall showing a smooth muscle coat with a lining of ciliated columnar epithelium. There is no cartilage – an important point of distinction from a bronchogenic cyst.



ESOPHAGEAL DIVERTICULUM



• Congenital diverticula very rare

• Most are acquired

• Histologically consist of all layers of esophageal wall


ACHALASIA



• See below under motility disorders


GASTRO-ESOPHAGEAL REFLUX DISEASE



• Some degree of gastro-esophageal reflux (GER) nearly universal in children

• GER of sufficient severity to cause symptoms or disease is termed gastro-esophageal reflux disease (GERD)

• Common in infants and children

• Most common under 6 months of age

• Presents with
image feeding difficulties

image vomiting

image failure to thrive

image respiratory symptoms

• Many mild cases treated without endoscopy

• Endoscopy and biopsy

• pH monitoring in difficult cases and differentiation from primary eosinophilic esophagitis


Histopathological features



• Changes can be patchy
image most severe in distal esophagus

image multiple biopsies required

• Basal cell hyperplasia (Fig 14.6)

• Intercellular edema

• Elongation of connective tissue papillae

• Congestion of capillaries

• Increased numbers of intraepithelial
image mononuclear inflammatory cells (’squiggle’ cells)

image eosinophils

image neutrophil polymorphs (unusual)
– if numerous consider fungal disease also

• Ulceration uncommon

• Non-specific stromal inflammation

image

Fig 14.6 Reflux esophagitis. Eight-year-old boy with short gut, on parenteral nutrition. Biopsy close to gastro-esophageal junction. Photomicrograph of esophageal biopsy showing basal cell hyperplasia with elongation of the connective tissue papillae that demonstrate vascular engorgement and perivascular hemorrhage, intercellular edema and an infiltrate within the epithelium of lymphocytes and eosinophils. The infiltrate is confined largely to the epithelium around the connective tissue papillae.



Differential diagnosis



• Eosinophilic esophagitis

• Infectious esophagitis

• Drug and chemical injury

• Crohn’s disease


COLUMNAR EPITHELIAL LINED ESOPHAGUS (CELE)



• Columnar epithelium replaces normal squamous epithelial covering of lower esophagus
image metaplastic process

• Irregular junction with squamous lined esophagus

• Requires certainty regarding exact site of biopsy

• Usually gastric cardiac type in children

• Barrett’s esophagus defined as CELE with goblet cells

• Barrett’s esophagus very uncommon in children

• More common in
image cases with severe longstanding GERD

image cases following TEF repair

image cystic fibrosis

image cerebral palsy


Histopathological features



• Irregular surface epithelium (Fig 14.7)
image often appears ‘villous’

• Mucus-secreting surface epithelium with underlying mucous glands

• Goblet cells

• Epithelial dysplasia very rare in children
image development of esophageal adenocarcinoma extremely rare in children

image

Fig 14.7 Columnar epithelial lined esophagus. Photomicrograph of a specimen from distal esophagus with a focus of gastric mucosa interdigitating with the squamous epithelium of the esophagus, which is inflamed. Such an appearance may be seen normally at the esophago-gastric junction and the interpretation critically depends on knowledge of the exact site of the biopsy.



EOSINOPHILIC ESOPHAGITIS



• Relatively common in children (Furuta et al 2007)

• Frequently associated with allergic disease
image asthma

image eczema

• Normal pH studies

• Symptoms include
image food intolerance

image dysphagia

image food ‘sticking’

• May have upper airway diseases such as
image laryngeal edema

image subglottic stenosis

• Diagnosis based on histological appearance in the correct clinical context
image not on histology alone

• Corrugated mucosa on endoscopy

• Do not respond to anti-reflux treatment

• Complications
image stenosis


Histopathological features (Ireland-Jenkin et al 2008)



• Usually entire esophagus involved

• > 20 eosinophils per high power field

• Eosinophils (Fig 14.8)
image frequently concentrated toward the surface

image clustered

• Activated mast cells present

• Ulceration uncommon

• Neutrophils not a feature

• Basal cell proliferation involving more than half the thickness of the epithelium

• Approx 50% have subepithelial fibrosis (Chehade et al 2007)

image

Fig 14.8 Eosinophilic esophagitis. Photomicrograph of esophagus showing hyperplastic squamous epithelial with intercellular edema and a heavy infiltrate of eosinophils scattered throughout the thickness of the epithelium.



Differential diagnosis and diagnostic pitfalls



• GERD
image requires clinicopathological correlation


INFECTIVE ESOPHAGITIS



• Almost always in the setting of immunocompromise

• In severely immunocompromised infections with multiple organisms occur


Candida



• Commonest infection of esophagus

• May be asymptomatic or cause dysphagia

• Endoscopically appears as white mucosal patches with underlying friable mucosa

• Histological features
image esophagitis with neutrophils

image pseudohyphae and spores detected with special stains (Fig 14.9)
– in inflammatory exudate on surface

– in the epithelium

image

Fig 14.9 Candida esophagitis. Large masses of fungal spores of Candida are seen in the debris attached to the mucosal surface of the esophagus.



Herpes simplex



• Immunocompromised hosts

• Reactivation of native HSV infection

• Symptoms
image fever

image nausea and vomiting

image chest pain

image dysphagia

image may be asymptomatic

• Endoscopically
image ulceration

image inflammatory exudates

image biopsy edge of ulcer

• Histological features
image esophagitis with neutrophils

image multinucleate epithelial giant cells

image intranuclear ‘ground glass’ inclusions (Fig 14.10)

image groups of macrophages

image

Fig 14.10 Herpetic esophagitis. Photomicrograph of the surface of the esophageal epithelium at the edge of an ulcer with intranuclear inclusions of HSV in squamous cells.



Cytomegalovirus



• Systemic symptoms

• Dysphagia

• Can co-exist with other opportunistic infections
image Candida

image Herpes simplex virus

• Endoscopically
image ulceration

image biopsy base of ulcers

• Histological features
image esophagitis

image characteristic CMV nuclear inclusions
– endothelial cells

– fibroblasts

image inclusions not usually seen in epithelial cells

• May cause strictures


Tuberculous esophagitis



• Very rare

• Secondary to infection in
image lung

image mediastinal nodes

image miliary TB

• Late event in the course of the disease

• Endoscopically
image ulcerating lesion

image may have stricture

• Histological features
image mucosal necrotizing granulomatous inflammation

• Complications
image tracheo-esophageal fistula

image perforation

image hemorrhage


CROHN’S DISEASE OF THE ESOPHAGUS



• Esophageal involvement relatively common
image can occur in isolation

• Usually lymphocytic esophagitis with (Fig 14.11)
image basal cell hyperplasia

image intercellular edema

image infiltration of epithelium by mononuclear cells

• May have well formed non-caseating epithelioid granulomas in lamina propria beneath epithelium (Fig 14.12)

• May be ulceration or stricture

image

Fig 14.11 Lymphocytic esophagitis in Crohn’s disease. Aphthous ulcers in duodenum and colon. Macroscopically normal ileum but granulomatous inflammation on biopsy. Photomicrograph of esophagus shows mild lymphocytic esophagitis with increased numbers of intraepithelial mononuclear cells associated with mild basal cell hyperplasia and intercellular edema. This appearance is very common in Crohn’s disease but is not specific.


image

Fig 14.12 Sixteen-year-old boy with Crohn’s disease treated with Infliximab. Stricture of esophagitis noted on endoscopy. Granulomas present in esophagus, stomach, ileum and colon. Photomicrograph of esophageal biopsy showing epithelial hyperplasia with a well formed epithelioid granuloma in the lamina propria immediately beneath the epithelium. A multinucleated giant cell is present. There is a scattering of lymphocytes in the surrounding connective tissue.



CHEMICAL AND DRUG-INDUCED ESOPHAGITIS



• Accidental swallowing of corrosive liquids in children

• Initial tissue necrosis edema and inflammation followed by repair with stricture formation (Figs 14.13, 14.14)

• Drug-induced inflammation tends to occur
image in the middle one-third

image at the site of strictures or other narrowings

• Not uncommon with high dose chemotherapy

• Superficial erosion

• Non-specific lymphocytic esophagitis

• May follow ingestion of iron containing medicines (Abraham 1999)
image crystalline iron deposition in the tissue

image erosions

• May also occur in stomach and duodenum (Figs 14.15, 14.16)

image

Fig 14.13 Caustic stricture of the esophagus from a 7-year-old boy. A tubular segment of esophagus cut longitudinally to demonstrate the severe fibrous thickening of the wall with occlusion of the lumen. The lumen is visible on the left hand side of the picture. The muscle coat visible as a slightly glistening darker layer on the left of the picture is replaced by white fibrous tissue on the right.


image

Fig 14.14 Caustic stricture of the esophagus. Photomicrograph showing intense hyperplasia of the epithelium. The underlying tissue consists of dense collagenous fibrous tissue with obliteration of muscle.


image

Fig 14.15 Photomicrograph of gastric mucosa showing crystalline iron deposition in gastric mucosa, evident as brown refractile material both on the surface and within the superficial lamina propria.


image

Fig 14.16 Same case as previous showing positive Perls’ reaction in the surface iron (to the right of the picture).



STOMACH



• Endoscopic biopsies for assessment of gastritis by far the most common gastric specimen for pediatric surgical pathologists

• Other entities such as Menetrier’s disease, dysplasia, GAVE and many other specific histological lesions seen in adults are exceptionally uncommon in children and are not described here
image see standard adult texts


GASTRITIS



• An important cause of abdominal pain in children

• Several different types

• Non-specific gastric changes may also be seen in a range of pediatric enteropathies
image see small intestine section for diagnostic features

• Any severely ill patient may also show non-specific acute gastritis
image clinically appears to be less common than adults


Helicobacter pylori gastritis



• Common in children but unusual in tertiary level practice as most detected and treated locally

• May not be apparent endoscopically

• Histological features well reported in adults
image childhood cases generally similar
– 0.5 µm spiral organism
· can be seen on H&E sections

· Giemsa stain enhances (Fig 14.17)

· present in surface mucus

image active gastritis
– neutrophils, eosinophils, plasma cells and lymphocytes (Fig 14.18)

image often with lymphoid nodules with germinal centers (Fig 14.19)
– nodularity of antral mucosa at endoscopy

• H. heilmanni in minority
image organism is longer with tighter spiral (Qualia et al 2007)

image

Fig 14.17 Helicobacter gastritis. Giemsa stained preparation at high power showing the organisms in the surface mucus. The organisms can be seen on H&E but are much more evident in the Giemsa preparations. They are confined to the mucus of the surface and the pits.


image

Fig 14.18 Helicobacter gastritis. Photomicrograph of a high power view of the lamina propria. Although neutrophil polymorphs are present, they are not as prominent as in adult patients with Helicobacter gastritis.


image

Fig 14.19 Helicobacter gastritis. Low power photomicrograph of gastric antral mucosal biopsy showing a diffuse inflammatory cell infiltrate in the lamina propria with lymphoid follicle and germinal center. The presence of germinal centers should always prompt a careful search for Helicobacter. They were present in this case.



Crohn’s disease associated gastritis



• Gastric involvement common

• More likely to have extensive disease

• Histological features variable
image non-caseating granulomatous gastritis (Fig 14.20)

image non-specific patchy chronic active gastritis

image non-specific chronic gastritis

• Presence of eosinophils in deep gastric lamina propria in pediatric gastritis is associated with Crohn’s disease

• Note that especially in children, non-specific gastritis may also be associated with ulcerative colitis
image not only Crohn’s disease

image

Fig 14.20 Gastric Crohn’s disease. Epithelioid granulomas in the superficial lamina propria. The epithelium is hyperplastic and there is a chronic inflammatory cell infiltrate in the lamina propria.



Lymphocytic gastritis



• Lymphocytic infiltrate in surface and crypt epithelium
image >20 lymphocytes / 100 surface epithelial cells (Fig 14.21)

• Association with untreated celiac disease
image More frequent in younger patients

image Often associated with vomiting

image Resolves with gluten-free diet

• Not all cases associated with gluten-enteropathy
image minority of HLO-associated gastritis

image minority of Crohn’s gastritis

image other autoimmune disease

image some apparently isolated

• Collagenous gastritis may be an associated entity
image subsurface epithelial band of collagenous ‘fibrosis’

image

Fig 14.21 Celiac disease with lymphocytic gastritis. Photomicrograph of a gastric biopsy from a case of celiac disease showing increased numbers of intraepithelial lymphocytes in both surface and glandular epithelium, akin to the appearance in the duodenum. Such patients tend to have vomiting as a symptom of their disease.



Drug-induced gastritis



• Compared to adults, children usually receive relatively few medications
image drug-induced gastritis uncommon

image chemotherapy associated changes most frequently biopsied

• Histological features can be highly variable
image similar to adult practice
– non-specific features through to severe ulceration

– may include granulomata

– may have numerous eosinophils


Autoimmune gastritis



• Relatively uncommon in children

• Usually associated with autoimmune enteropathy and/or other autoimmune disease

• Histological features variable
image non-specific inactive gastritis

image active gastritis

image relative neuroendocrine cell hyperplasia


Eosinophilic gastritis



• Eosinophils may be component of other types of gastritis
image especially Crohn’s associated gastritis

image drug induced gastritis

image infectious gastritis

• If large numbers of eosinophils are present in surface epithelium and lamina propria consider as eosinophilic gastritis
image may be associated with
– peripheral eosinophilia

– asthma

– other autoimmune disease

– food allergy / hypersensitivity


HYPERTROPHIC PYLORIC STENOSIS



• See below under motility disorders


GASTRIC VOLVULUS



• Very rare in children

• Can be associated with apslenia

• Unusual to receive surgical specimens from such cases
image non-specific secondary features


GRAFT-VERSUS-HOST DISEASE



• See specific section below


GASTRIC TUMORS



• Very rare in childhood

• Gastric carcinoma almost never occurs

• Stromal tumors may occur
image see specific section below

• Polyps rare
image see small intestine


SPONTANEOUS PERFORATION OF THE GI TRACT



• In this context means isolated perforation with no other detectable underlying disease process
image does not include those with demonstrable acute ischemia, necrotizing enterocolitis (NEC), etc

• Reported more in low birth weight infants
image even those without NEC

• Probably ischemic in nature

• Usually gastric
image can affect colon, Meckel’s diverticulum

• May be associated with congenital focal defective musculature

• May rarely be associated with underlying genetic condition
image Ehlers–Danlos syndrome


Histopathological features



• Non-specific features secondary to perforation (Fig 14.22)

• No detectable underlying cause such as acute ischemia

• Other causes such as vasculitis etc must always be excluded

image

Fig 14.22 Spontaneous perforation of the stomach. Photomicrograph from the edge of the perforation showing hemorrhagic necrosis of the tissues. This is a non-specific appearance of ischemic-type damage.



SMALL INTESTINE



INTESTINAL ATRESIA



• Intrauterine process resulting in incomplete bowel lumen

• Duodenal atresia
image presumed developmental

image mainly associated with trisomy 21

image rarely submitted for pathological assessment
– usually treated with duodenoduodenostomy

• Intestinal atresia
image presumed due to intrauterine insult

image ischemic / hypotensive episode

image jejunum and ileum affected

image isolated or multiple

image more commonly submitted
– treated with resection and anastomosis


Histopathological features



• Intestinal atresia
image discontinuous lumen

image atretic segment (Fig 14.23)

image fibrosis (Fig 14.24)
– focal muscularis replacement (Fig 14.25)

image dystrophic calcification

image pigment-laden macrophages

image

Fig 14.23 Ileal atresia. Resected specimen showing a thread-like segment of stenotic bowel with a more proximal part with intense dilatation because of the obstruction.


image

Fig 14.24 Ileal atresia. Photomicrograph showing the junction of atretic and patent segment of intestine. The bowel ends blindly with fusion of all the layers into a fibrovascular band without recognizable bowel wall structures. Hemosiderin is frequently present at such sites indicating previous hemorrhage.


image

Fig 14.25 Stenosis of bowel following in-utero ischemia. Photomicrograph demonstrating the thickened submucosa with focal fresh hemorrhage. The muscularis mucosae is largely absent – a sign of previous ulceration. The muscular coat is also focally deficient.



MECKEL’S DIVERTICULUM AND RELATED VITELLOINTESTINAL REMNANTS



• Embryonic vitellointestinal duct joins lumen of midgut to yolk sac
image usually obliterated early in development
– can persist
· as fistula between umbilicus and ileum

– only parts may persist
· proximal part as Meckel’s diverticulum

· distal part as umbilical sinus / cyst / granuloma


MECKEL’S DIVERTICULUM



• 1–4% of population

• May be completely asymptomatic

• Symptoms in about one-fifth of cases
image ulceration
– either in the diverticulum or adjacent small bowel

image hemorrhage

image perforation

image foreign body can lodge to cause perforation

image may form lead point for intussusception

image may have fibrous attachment to umbilicus
– cause bowel obstruction or volvulus


Histopathological features



• Antimesenteric border of terminal ileum approx 30cm from ileo-cecal (IC) valve

• Up to about 8cm long (Fig 14.26)

• May be long and tubular or squat and almost cystic

• Tip may be bifid or nodular

• All components of normal bowel wall present

• Muscle coat may be very attenuated at the tip or distorted by heterotopic tissue

• Lined usually by
image ileal mucosa

image may have gastric body mucosa lining in minority (Fig 14.27)
– Helicobacter may colonize

image rarely colonic tissue

• May see ulceration or bleeding point

• May have nodules of pancreatic tissue (including islets) in wall (Fig 14.27)

• Serosa may show fibrosis or inflammation

image

Fig 14.26 Meckel’s diverticulum. Photograph demonstrating the excised specimen of piece of ileum with the diverticulum arising from its antimesenteric border, being long and tubular with slightly bulbous end.


image

Fig 14.27 Meckel’s diverticulum. Photomicrograph showing gastric body mucosa lining the distal part of the diverticulum. In the submucosa there is a nodule of heterotopic pancreatic tissue.



OMPHALOMESENTERIC CYSTS AND SINUS



• Present as umbilical discharge or granulation tissue

• Lined by
image small bowel mucosa (Fig 14.28)

image gastric type mucosa

image colonic mucosa

• May contain pancreatic tissue

• May ulcerate
image replacement by granulation tissue
– umbilical ‘granuloma’

image

Fig 14.28 Umbilical granuloma. Skin with an area of enteric mucosa that is inflamed. A channel lined by similar epithelium can be seen extending into the deeper tissue.



DUPLICATION CYSTS



• See discussion under esophagus


Histopathological features



• Two layered muscularis propria with outer layer fused with normal intestine
image contains a myenteric plexus

image mucosal lining usually enteric mucosa
– gastric mucosa also common (Fig 14.29)

image

Fig 14.29 Ileal duplication cyst. Photograph demonstrating an excised cyst in the wall of the length of small intestine. It does not communicate with the lumen and has a pearly white lining.



INTUSSUSCEPTION



• Invagination of bowel into the bowel distal to it

• Mainly ileocecal

• Mainly (>90%) infants
image when occurring in other ages or at other sites more likely to be secondary to another specific pathology

• Results in secondary ischemic damage to bowel

• Presents with
image abdominal pain

image ’red-currant jelly’ stool

image palpable abdominal mass

• Many cases can be reduced medically
image only those not responding come to surgery and resection


Histopathological features



• Resected mass comprises
image outer layer of thinned distended bowel – the intussuscipiens

image inner layer of everted invaginated bowel – the intussusceptum

• Mesentery of intussusceptum is stretched and congested

• Lead part of the intussusceptum may show a mass that may be
image lymphoid hyperplasia secondary to viral infection (Figs 14.30, 14.31)

image polyp

image Meckel’s diverticulum (Fig 14.32)

image duplication cyst

image tumor

image heterotopic pancreas

• Intussusceptum is frequently infarcted and hemorrhagic

• Histologically the intussusceptum shows
image edema

image hemorrhagic infarction

Related posts:

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  3. DERMATOPATHOLOGY
  4. RENAL PATHOLOGY

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Jun 18, 2016 | Posted by in PEDIATRICS | Comments Off on GASTROINTESTINAL PATHOLOGY

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