2- Stomach

Page 9: Gastric Adenoma

  • Characteristics:

    • Generally solitary, with the majority located in the antrum of the stomach.

    • Almost always associated with a background of chronic gastritis featuring atrophy and intestinal metaplasia.

  • Histological Features:

    • Composed of intestinal-type columnar epithelium displaying epithelial dysplasia.

  • Cancer Risk:

    • The likelihood of developing adenocarcinoma from gastric adenomas correlates with the lesion's size, particularly if it exceeds 2 cm in diameter.

Page 10: Pathogenesis

  • Chronic Gastritis:

    • Most commonly linked to infection by H. pylori, which facilitates the onset and advancement of cancer.

  • Viral Association:

    • Approximately 10% of gastric adenocarcinomas are associated with Epstein-Barr virus (EBV) infection.

Page 11: Morphology

  • Types of Gastric Cancers:

    • Gastric cancers can be classified into two main types: intestinal and diffuse.

  • Intestinal Type:

    • Characterized by bulging masses composed of glandular structures that are similar to those found in esophageal and colonic adenocarcinomas.

  • Diffuse Type:

    • Exhibits an infiltrative growth pattern, consisting of discohesive cells featuring large mucin vacuoles that expand the cytoplasm and displace the nucleus to the periphery, characteristic of signet ring cell morphology.

    • In many cases, endoscopic lesions may not be observed, allowing for the possibility of missed diagnoses.

    • This type can cause the gastric wall to become stiff, leading to a "leather bottle" appearance known as linitis plastica.

Page 12: Prognosis

  • Prognostic Indicators:

    • The depth of tumor invasion and the extent of nodal and distant metastasis at the time of diagnosis are the most significant prognostic factors for gastric cancer.

  • Survival Rate:

    • The 5-year survival rate for advanced gastric cancer is alarmingly low, remaining below 20%.

Page 13: Spread of Gastric Cancer

  • Local Spread:

    • Cancer can invade the surrounding structures through the stomach wall, affecting the pancreas, liver, and esophagus.

  • Transcoelomic Spread:

    • Involves dissemination to the peritoneum.

  • Lymphatic Spread:

    • Metastasis may occur to regional lymph nodes (L.N.).

  • Hematogenous Spread:

    • Cancer can spread through the bloodstream to vital organs such as the lung, liver, and brain.