Adenocarcinoma

Adenocarcinoma- histological (Courtesy of BioMed Image Archive)

• Adenocarcinoma is the most common gastric neoplasm in small animals.
  • This is a tumour of the mucosal epithelium.
• These are genreally found in the fundus (particularly along the lesser curvature), and in the pylorus.
• There are two main internal appearances of gastric adenocarcinoma, both of which show thickened, oedematous, pale and firm tissue:
  

  Adenocarcinoma- gross (Courtesy of BioMed Image Archive)
  1. A diffuse infiltration of gastric mucosa by neoplastic glandular epithelial cells.
     • Causes a diffuse rugal thickening.
  2. A more solitary lesion that is seen as a thick plaque-like lesion
     • Generally has a central erosion/ulceration of the tumour tissue.
       • Distinguishable from a peptic ulcer as the edges of the eroded area are raised and thickened (tumour tissue).
• The external appearance of an affected stomach can include thickening of the draining lymphoid vessels due to tumour infiltration ('cording of the lymphatics') and evidence of a scirrhous reaction to the carcinoma.
• Adenocarcinomas are locally aggressive and spread via the lymphatics to the lymph nodes, lung, liver and adrenal glands.