BARRETT’S OESOPHAGUSFOR THE

HISTOPATHOLOGISTBy

Dr. Varughese George

Introduction• Replacement of the lower oesophageal squamous mucosa by metaplastic

glandular mucosa as a result of Gastro-Oesophageal Reflux Disease.

• The escalating incidence of columnar lined oesophagus (CLO) is coupled with marked increase in the incidence of its malignant complication.

• Oesophageal cancer is

– 9th most common cancer

– 5th most common cause of cancer death.

• 8 fold increase in adenocarcinoma over the past 30 years.

• Increased incidence found in Western Europe and North America.

Introduction

Barrett esophagus and dysplasia appear to be precursors or markers of adenocarcinoma development

• 10% of patients with gastroesophageal reflux will have Barrett esophagus• 10% of patients with Barrett esophagus will have dysplasia• 10% of patients with Barrett esophagus will have adenocarcinoma at the

time of initial diagnosis• Longterm followup of patients with low grade dysplasia in Barrett

esophagus (Sharma 2004)– 10% progress to high grade dysplasia– 3% progress to carcinoma

• Followup of patients with high grade dysplasia in Barrett esophagus (Konda 2008)– 40% develop carcinoma

• 87% of these are intramucosal• Only 13% are invasive into submucosa or beyond

A short history of Barrett’s oesophagus

• Lyall, Br J Surg 1937: “ulcers occur in the oesophagus, and are surrounded by heterotopic gastric mucosa”

• Barrett NR, Br J Surg 1950: “chronic peptic ulcer of the oesophagus and oesophagitis”

2 distinct lesions :

– Reflux oesophagitis

– Peptic ulcer of the oesophagus, that correspond to congenital short oesophagus with gastric ulcer in the mediastinal stomach

• Morson & Belcher, Br J Cancer 1952: “Adenocarcinoma of the oesophagusand ectopic gastric mucosa”

A short history of Barrett’s oesophagus

Some may be worried because I have changed my opinion•The lesion should be called “the lower esophagus lined by columnar epithelium”•It is probably the result of a failure of the embryonic lining of the gullet to achieve maturity.

Lord RV. Norman Barrett, “Doyen of esophageal surgery”. Ann Surg 1999;229:428.

Risk Factors

• Sex – male > female

• Age – middle-age

• Race – Caucasian

• Overweight

• Smoking and intake of alcohol

• Family history

• Acid reflux.

• Reflux of bile and alkali from the duodenum.

• Lack of H pylori infection of stomach encouraging a high stomach acid level.

Which kind of epithelium lines Barrett’s oesophagus?

• Initial descriptions :

– “ectopic gastric mucosa”.

– Accurate reading : “columnar cells, mucus secreting units, tubular glands, no oxyntic cells” (Barrett 1957)

• Morson & Belcher 1952: Intestinal metaplasia

• Paull et al 1976 : Classical description of 3 types of metaplastic epithelium

• “Modern” period : Intestinal metaplasia (goblet cells) is mandatory for the diagnosis, but...

Gross pathology

• Barrett’s mucosa is usually represented by a well-defined area of salmon-pink, velvety mucosa similar to the adjacent gastric mucosa.

• It has irregular margins and may contain islands of residual squamous, pearly white esophageal mucosa, or it may be ulcerated.

• It is usually limited to the lower third of the esophagus, but in severe cases, it may extend to the middle and upper esophagus

Endoscopic Diagnosis of BE

Diagnosis – Endoscopic demonstration of at least 3cm of columnar-lined epithelium present in the lower oesophagus

• Long segment - Barrett's mucosa extends more than 3cm.

• Short Segment CLO – Barrett's mucosa extends less than 3cm.

• UltraShort Segment CLO – Barrett's mucosa extends less than 1 cm with microscopic demonstration of intestinal metaplasia at the cardia.

Practical Diagnostic Definitions

3 types of columnar epithelium (Paull 1976)

1. “Specialized” or intestinal

2. Cardiac (junctional)

3. Fundic (gastric)

“Classical”: circumferential columnar epithelium >3 cm above the oesophago-gastric junction (OGJ)

1 2 3

ACG and BCG criteria for Diagnosis

ACG - Extension of salmon-colored mucosa into the tubular esophagus extending ≥1 cm proximal to the gastroesophageal junction with biopsy confirmation of Intestinal Metaplasia.

BCG - Endoscopically apparent area above the oesophagogastricjunction that is suggestive of Barrett’s which is supported by the finding of columnar lined oesophagus on histology. The presence of areas of intestinal metaplasia (IM), although often present, is not a requirement for diagnosis.

The endoscopic appearance of Barrett esophagus showing an irregular squamocolumnar junction with a salmon-pink tongue extending into the tubular esophagus.

•Damage to the esophageal differentiated cells in the superficial and parabasal compartments of the esophagus.

•Basal progenitor cells move into denuded areas after the gastric acid-peptic content from the stomach has eroded the squamous mucosa.

•Damage to a deeper compartment involving the squamous epithelial stem cells in the basal compartment of the papillae.

•Persistent gastroesophageal reflux causes multipotential stem cells to differentiate into columnar, mucin-secreting epithelium resistant to acid and bile.

•Barrett esophagus composed of a superficial, foveolar-like component (with a villiform surface) and underlying mucous glands, which have focally split the muscularis mucosae.

•The diagnostic goblet cells are evident even at low power.

•High-magnification view of intestinal metaplastic epithelium of Barrett esophagus.•Numerous goblet cells are dispersed among columnar cells.

•Alcian blue/periodic acid-Schiff (PAS) stain in Barrett esophagus with incomplete metaplasia.•The goblet cells stain intensely blue with the Alcian blue portion of the stain due to the presence of acid mucins.•The columnar cells between the goblet cells stain with PAS, indicating the presence of neutral mucins.

• Cardiac-type mucosa in a segment of Barrett esophagus.

• When compared to the normal gastric cardia, there is atrophy of cardiac-type glands and inflammation within the lamina propria.

• Intestinal metaplasia is seen in the adjacent mucosa.

Pathology and Diagnosis

• Patchwork of intestinal, cardiac and fundic phenotypes

• No specific IHC for demonstration of intestinal metaplasia

• MUC-1 and MUC-6 were 90% specific for goblet cells in CLO.

• Use of – cytokeratin 7 staining for glandular

epithelium

– cytokeratin 20 staining for surface epithelium.

Pathology and Diagnosis

• Intestinal metaplasia in CLO is preceded by development of intermediate or ‘transitional’ type of epithelium.

• A unique type of multilayered epithelium is demonstrable at the squamocolumar junction.

• Cardiac Metaplasia includes squamous epithelium overlying the crypts with intestinal metaplasia and hybrid glands.

• Presence of non-goblet columar cells that stain with Alcian Blue – blue cells – maybe a marker for intestinal metaplasia.

Pseudogoblet Cells

• Foveolar epithelial cells with prominent cytoplasmicdistention.

• Has a hazy, ground glass appearance to their cytoplasmic mucin.

• Contains neutral mucin.

• Tends to aggregate in clusters.

Goblet V/S Pseudogoblet Cells

In contrast to pseudogoblet cells, true goblet cells are sparsely distributed (arrowheads).

In contrast to pseudogoblet cells, true goblet cells (arrowheads) have a deeply basophilic appearance on a PAS/AB.

The pathological reporting strategy for reporting CLO ( BSG)

Cytology and CLO

• No generally accepted role of cytology in establishing diagnosis of CLO.

• Relies on identification of goblet cells within sheets of benign glandular cells.

• Goblet cells exhibit a single large cytoplasmic vacuole that displaces the nucleus, creating a crescent-shaped nucleus.

• The diameter of the vacuole is at least three times the width of a normal columnar cell.

• Brushing cytology is a good screening tool for dysplasia.

• Unable to differentiate between dysplasia and invasive carcinoma.

• Difficult to differentiate low grade dysplasia from inflammatory changes.

Prague Classification

The Riddell’s and Vienna classification for gastrointestinal neoplasia

Negative for Dysplasia

• Columnar epithelium with or without intestinal metaplasia

• The surface columnar cells are well spaced, regular, mature and have oval to round, basally located nuclei,1-2 times the size of a mature lymphocyte

Negative for Dysplasia• Columnar epithelium shows

foveolar type mucin in the apices of the surface cells.

• Basally located, small and ovoid nuclei.

• Sparse round cell population in the lamina propria.

• Mild hyperplastic features with pseudostratied nuclei that retain their orientation

Negative for Dysplasia

• Regular surface epithelium

• Apically oriented cytoplasm and basally oriented nuclei.

• Lamina propria contains sparse lymphocytes and plasma cells.

• A close up of part of the surface shows goblet cells

Indefinite for Dysplasia

• Histological abnormalities that meet criteria for dysplasia but are occuring in the setting of inflammation

• Histologic abnormalities resembling dysplasia but may be “reactive”, a result of inflammation and which would disappear once inflammation resolves

Indefinite for Dysplasia

Features of dysplasia are present:

• Nuclear enlargement and hyerchromasia

• Focal loss of cytoplasmicmaturation

• Focal loss of basal orientation of nuclei

Changes of dysplasia + inflammation = indefinite for dysplasia

This image of Barretts shows neutrophilicinfiltration of the surface epithelium

Indefinite for Dysplasia

• Neutrophils infiltrating lamina propria and surface epithelium

• Features of dysplasia:– Focal loss of cytoplasmic

maturation– Nuclear enlargement

and hyperchromasia of surface cells

– Focal loss of basal polarity of surface nuclei

Changes of dysplasia + inflammation = indefinite for dysplasia

Low Grade Dysplasia• Enlarged, crowded, irregular,

hyperchromatic and ovoid nuclei.

• Atypical mitoses may be present.

• Stratification is often present.

• Architectural change including villosity may be present.

• Loss of basal-luminal maturation/differential axis.

High Grade Dysplasia

• Enlarged spheroidal nuclei with open chromatin pattern with nucleoli.

• Atypical mitosis are usually present.

• Stratification with pronounced cellular disorganisation.

• Architectural changes villosity, glandular budding and complex glandular structures is often present.

• Loss of basal-luminal maturation/differential axis.

• This complex glandular proliferation shows striking cytologic atypia and represents at least

• high-grade dysplasia in Barrett esophagus.

• In some areas, the glands are back-to-back with essentially no intervening lamina propria.

Cytological and architectural features of low‐grade and high‐grade dysplasia in Barrett's

oesophagus

Intramucosal adenocarcinoma• Neoplastic cells make their

way to the basement membrane , muscularismucosae or lamina propria.

• Effacement of architecture of the lamina propria

• A syncytial growth pattern may also be observed.

• Desmoplasia is absent or not completely developed.

Adenocarcinoma

Nests of mucin producing cells of adenocarcinoma undermining squamous mucosa

Adenocarcinoma

Adenocarcinoma infiltrating as single cells (diffuse or signet ring type). Although the cells resemble plasma cells, they are larger and many have vacuoles.

Molecular Markers

• Limited utility.

• p53 labels most HGD with nuclear staining should extend to the mucosal surface.

• Nuclear Ki-67 labeling extending to superficial cells correlates with LGD on routine histology, whereas extensive surface labeling correlates with HGD.

• Cyclin D1 labels up to 45% of cases.

• Beta-catenin is another useful marker for separating LGD from reactive metaplastic changes.

• a-Methylacyl coenzyme A racemase (AMACR) was also found useful in distinguishing reactive and dysplastic epithelium.

p53 Immunostaining in Barrett’s oesophagus

p53 immunostaining of Barrett mucosa showing strong nuclear positivity and negativity in high- and low-grade dysplasia, respectively.

Surveillance

• Detects neoplastic progression at an early stage and prevent cancer-related death.

• Patients with endoscopy suggestive of BE should have 4-quadrant biopsies at minimum intervals of every 2 cm of the BE segment.

Surveillance

New techniques for in situ endoscopic diagnosis of neoplasiacomplicating CLO

Summary

• Barrett’s oesophagus is an endoscopic diagnosis corroborated by histology.

• The characteristic histological features include

– Patchwork of cardiac,fundic and intestinal epithelial types

– Hybrid glands

– Multilayered epithelium

• The role of intestinal metaplasia in the neoplastic sequence of Barrett’s oesophagus is undeniable and much more controversial in diagnosis.

• Treatment of Barrett’s oesphagus by acid suppressants cause squamousre-epithelialisation thus causing confounding biopsy appearances.

Summary

• The low and high grade categories should be used by pathologists for reporting dysplasia in CLO.

• Pathologists should use the category ‘indefinite for biopsy’ when pathological features are equivocal due to inflammation or other features.

• Endoscopic appearances do not correlate well with histopathologicdiagnosis, thus emphasizing the need for comprehensive sampling of the segment.

• 25-50% of high grade dysplasia have co-existent adenocarcinoma.

• The diagnosis of high grade dysplasia should be confirmed by a second expert like a specialized gastrointestinal pathologist.

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3. Voltaggio L, Montgomery EA, Lam-Himlin D. A clinical and histopathologicfocus on Barrett esophagus and Barrett-related dysplasia. Arch Pathol Lab Med. 2011;135:1249–1260.

4. Anjarwalla SM, Shepherd NA. Barrett’s oesophagus for the practicisinghistopathologist. Recent Advances in Histopathology 22 2007;3:45-65

5. Zibadi S, Coppola D. Surgical and Molecular Pathology of Barrett Esophagus. Cancer Control : Journal of the Moffitt Cancer Center. 22: 177-85.

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