PA23.9 | GI Morphology — Practical — Summary & Reflection

REFLECT

You have now worked through the major GI specimen types. Before completing this module, write a brief 3-point summary (in your own words, not copied) for ONE of the following pairs:

Option A: How would you distinguish TB ulcer from Crohn disease on a single histology slide?
Option B: What three microscopic features separate a tubular adenoma from invasive colorectal adenocarcinoma?

Write your response in your notebook. There is no auto-grading — the purpose is to force retrieval practice, which is the single most evidence-backed study technique. If you cannot construct the three points from memory, revisit the relevant section before the practical.

KEY TAKEAWAYS

Key take-aways from this module:

1. Systematic reading approach (5 steps: site → gross pattern → micro architecture → benign/malignant → diagnosis) prevents pattern-matching errors in the exam.

1. Peptic ulcer gross: round, punched-out, clean base, converging folds. Micro: 4 zones in order — fibrinopurulent exudate → non-specific inflammation → granulation tissue → fibrosis/scar.

1. Intestinal ulcers compared: TB = caseating granulomas, transverse; Crohn = non-caseating granulomas, transmural, skip lesions; UC = crypt abscesses, mucosal only, continuous; Typhoid = typhoid cells over Peyer's patches, longitudinal.

1. Tumour micro signatures: SCC = keratin pearls; gastric intestinal = gland-forming with atypia; gastric diffuse = signet-ring cells, no glands; colorectal adenocarcinoma = gland-forming with dirty necrosis; adenomatous polyp = dysplastic glands/villi without invasion.

1. Benign vs malignant ulcer edge: benign = reactive uniform epithelium; malignant = atypia, desmoplasia, invasion.

Head into the practical session with these five anchors — and use the 2x2 composite grid to self-test identification of all four patterns.