Introduction

Endoscopic examination of the stomach plays an important role in the investigation of patients with dyspepsia, haematemesis and/or melaena, and upper abdominal pain. While biopsy is always necessary when gastric polyps, ulcers, or areas of mucosal irregularity have any features suggesting a neoplastic process,¹ there is general agreement that biopsy of the normal stomach does not increase the likelihood of detection of neoplasia and that it is not necessary.² While some authors recommend gastric biopsy to characterise gastritis,³ there is poor correlation between ‘endoscopic gastritis’ (redness of the mucosa) and demonstration of gastritis on histological assessment of biopsies.⁴ Moreover, the diagnosis of Helicobacter gastritis can be made by less expensive investigations (e.g. the urease test) and there is no evidence that detection of intestinal metaplasia or grading of chronic active gastritis currently influences management of the patient.⁵ Recommendations for endoscopy biopsy practice differ between pathology departments and countries, but histological assessment of endoscopic gastric biopsies remains a major component of the histopathology department’s workload and requires close co-operation between the clinician and the pathologist.

General Considerations

Most gastric biopsies are taken for assessment of gastritis, ulceration, or polyps, or for exclusion of dysplasia or malignancy. The standard laboratory approach to the gastric biopsy is to cut routine haematoxylin and eosin (H&E)-stained step sections at two or three levels, with the option of cutting additional levels depending on the initial morphological findings. Some laboratories perform routine stains for Helicobacter pylori and for mucins (to identify intestinal metaplasia) on every gastric biopsy, but there is conflicting evidence over the clinical value and effectiveness of this approach.^{6, 7} The updated Sydney classification system guidelines (see later) suggested that a histochemical stain (e.g. Giemsa, cresyl fast violet) is appropriate when Helicobacter pylori are not identifiable on H&E examination in the setting of gastric inflammation.⁸ Others prefer to use immunohistochemistry, particularly after antibiotics or proton pump inhibitor therapy, because it appears to be more sensitive for the detection of small numbers of Helicobacter pylori and the coccoid forms, the latter possibly representing dead organisms.^{6, 9, 10} The Royal College of Pathologists, UK, recommends a Helicobacter stain if characteristic inflammation is present, no Helicobacter are apparent on H&E, and no clinical test (e.g. urease test) has been performed.¹¹

Other histochemical stains and immunohistochemistry (Table 12.1) may be useful in the appropriate setting, for example a Perls stain to confirm iron tablet debris in iron pill gastritis¹³ or a Ziehl–Neelsen stain in granulomatous inflammation.

Classification of Gastritis

There have been many different classifications of gastritis. The current ICD-10 classification (Table 12.2) is a mixture of aetiology and phenotype,¹⁴ while the more recently proposed Kyoto classification is based entirely on aetiology (Table 12.3).¹⁵ Pathologists will be far more familiar with the Sydney System for classification and grading of gastritis (Table 12.4).^{8, 16}

Related posts:

Chapter 4 – Transplantation, Immunodeficiency, and Immunosuppression Chapter 5 – Drug-Induced Gastrointestinal Disease Chapter 11 – Infections of the Oesophagus and Rare Forms of Oesophagitis Chapter 25 – Ileal Pouch Anal Anastomosis Chapter 20 – Microscopic Colitis Chapter 21 – Inflammatory Bowel Disease Diagnosis

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