Histology Course S I 4 Department of Pathology, University of Zurich Histokurs

S I 4 adenocarcinoma, diffuse type according to Lauren  IHC: LU-5 further information (German) on HiPaKu
  ICD-10: C16.9; ICD-O: 8145/3

54-year-old male with weight loss, increasing loss of appetite and anaemia. The CT scan reveals extensive thickening and infiltration of the gastric antrum. Gastric resection (Billroth II)

- Immunohistochemistry of the specimen shows less contrast compared to the H&E stain. Shown here is the antral mucosa with underlying thickened submucosa containing inflammatory infiltration with follicles. Underneath is the muscularis propria which (alike the thickened submucosa) is also infiltrated with tumor tissue.
- The tumour consists of individual cells or groups of cells and does not form glandular strings
- Small groups of tumour cells or individual cells are invading the pre-existing structures and thus it is not possible to define a clear border between tumour and normal tissue. Hence the nomenclature "diffuse type".
- The antibody LU5 stains with a brown reaction product in epithelial cells which is nicely shown on the surface epithelium. This antibody also defines carcinoma cells (epithelial phenotype) and makes these distinct as such. In an H&E preparation it is diffcult to distinguish the tumour cells from scar tissue or inflammatory infiltration.