4,Stomach

Stomach Anatomy

  • Key Structures

    • Esophagus

    • Cardiac Area

    • Pyloric Sphincter

    • Lesser Curvature

    • Fundus

    • Antrum

    • Greater Curvature

Histology of Gastric Mucosa

Cardiac Mucosa

  • Types of Cells:

    • Parietal (oxyntic) cells: secrete HCl

    • Mucin-secreting cells: provide mucus layer

    • Chief (zymogen) cells: secrete pepsinogen

    • Endocrine cells: release hormones like gastrin

  • Gland Types:

    • Cardia glands: short tubular glands

    • Fundic mucosa: long tubular glands

    • Pyloric mucosa: similar to antrum

Layered Structure

  • Foveolar Compartment: Protects mucosa

  • Glandular Compartment: Contains gastric glands

Pathology of the Stomach

Common Disorders

  • Inflammatory Disorders:

    • Gastritis

    • Erosive and ulcerative lesions

  • Neoplastic Lesions:

    • Gastric adenocarcinoma

    • MALT lymphoma (Mucosa-Associated Lymphoid Tissue)

Ectopic Tissue Conditions

  • Ectopic Gastric Mucosa:

    • Commonly found in the upper third of the esophagus (inlet patch)

    • Can cause dysphagia and esophagitis due to acid secretion.

  • Ectopic Pancreatic Tissue:

    • Less common, may cause inflammation, especially at pylorus.

Diaphragmatic Hernia

  • Caused by incomplete diaphragm formation.

  • Can lead to pulmonary hypoplasia.

Congenital Anomalies

  • Types:

    • Posterolateral (Bochdalek) Hernia

    • Anterolateral (Morgagni) Hernia

    • Hiatal hernia

Gastritis Types

Acute Gastritis

  • Causes: H. pylori, NSAIDs, excessive alcohol

Chronic Gastritis

  • Types:

    • Type A (autoimmune)

    • Type B (H. pylori-related)

    • Type AB (antral-body gastritis)

    • Chemical (reflux gastritis)

H. pylori Infection

  • Most common cause of chronic gastritis

  • Transmitted primarily via fecal-oral route.

  • Associated with peptic ulcers and gastric cancer.

Non-Invasive Diagnostic Tests

  • Urea breath test

  • Serology for antibodies

  • Fecal bacterial detection

Peptic Ulcer Disease (PUD)

  • Ulceration occurs in stomach or duodenum.

  • Often associated with H. pylori and NSAID use.

Symptoms

  • Epigastric pain, nausea, vomiting, iron deficiency anemia.

Morphology of Ulcers

  • Characterized by sharply punched-out defects, often solitary.

Gastric Cancer

  • Common Forms:

    • Adenocarcinoma (90% of gastric cancers)

    • Lymphomas, carcinoids

  • Risk Factors:

    • H. pylori infection

    • Diet (high nitrites)

    • Low socioeconomic status

Diagnosis and Prognosis

  • Endoscopic biopsy for detection.

  • Prognosis tied to depth of invasion and metastasis.

Miscellaneous Conditions

Bezoars

  • Foreign bodies formed in the stomach, often seen with mental illness.

  • Types include trichobezoars and phytobezoars.

Gastric Polyps and Tumors

Non-Neoplastic Polyps

  • Hyperplastic and inflammatory polyps are common.

Neoplastic Tumors

  • Gastric adenomas and cancers have significant risk for malignancy.

Gastrointestinal Stromal Tumor (GIST)

  • Most common mesenchymal tumor in the abdomen.

  • Arises from interstitial cells of Cajal with potential for metastasis.

Neuroendocrine Neoplasms

  • Well-differentiated neuroendocrine tumors often associated with hormonal symptoms.

Morphology

  • Tumors may be intramural or submucosal and firm in texture.

Conclusion

  • Various gastric pathologies present significant clinical challenges, from benign conditions like gastritis to severe conditions such as gastric cancer. Understanding the anatomy and histology of the stomach is crucial for proper diagnosis and treatment.