Sitting FRCPath Part 2? This case is a free sample from our Part 2 programme.
See the FRCPath Part 2 course →The FRCPath Part 2 histopathology exam tests whether you can report a slide the way you would on the bench: describe what you see, commit to a diagnosis, and say what you would do next, all against the clock. This practice case is built to feel like a short surgical station. Set the timer, look at the virtual slide, write your answer, then mark yourself against the model answer.
The Case: GI Biopsy Short Surgical
Practice case · short surgical
Appendix and small bowel biopsy
Clinical details: A middle-aged adult with prolonged watery diarrhoea and weight loss undergoes endoscopic biopsy of the appendix and small intestine.
Drag to pan · pinch or double-tap to zoom · use the + / − buttons. Look at the luminal surface at high power.
Write Your Answer
Structure it as you would in the exam: a short description, your diagnosis, and any further work-up or comment.
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Model Answer and Discussion
Description
Sections show appendiceal and small intestinal mucosa. Numerous small (about 2–5 µm), round, basophilic bodies sit along the luminal surface of the epithelium, at the brush border. The appendix shows lymphoid follicular hyperplasia and a lamina propria infiltrate with prominent eosinophils. The muscularis propria is attenuated and the serosa mildly congested. There is no dysplasia or malignancy.
Further work-up and comment
- Modified Ziehl–Neelsen and Giemsa stains to highlight the organisms; immunohistochemistry or immunofluorescence where available.
- Stool examination for acid-fast oocysts, or stool antigen or PCR testing.
- Assess immune status, including HIV testing and CD4 count, and look for co-infection such as CMV or microsporidia.
- Comment: usually self-limiting in immunocompetent patients, but causes severe, persistent watery diarrhoea in immunocompromised patients.
Differential diagnosis: GI protozoa on biopsy
| Organism | Size | Where it sits | Helpful stain or feature |
|---|---|---|---|
| Cryptosporidium | 2–5 µm in tissue; oocysts 4–6 µm | At the brush border: intracellular but extracytoplasmic | Oocysts acid-fast (modified ZN) |
| Cyclospora | Oocysts 8–10 µm | Within enterocyte cytoplasm | Variably acid-fast; autofluorescent |
| Cystoisospora (Isospora) | Oocysts 20–30 µm | Within enterocytes, in a parasitophorous vacuole | Acid-fast; may be accompanied by eosinophils |
| Microsporidia | Spores 1–2 µm | Intracytoplasmic, often supranuclear | Modified trichrome; Gram or Warthin–Starry |
| Giardia | Trophozoites 10–15 µm | Free in the lumen, close to villi; not attached as dots | Pear-shaped, binucleate (“falling leaf”) |
Where candidates lose marks
- Describing the dots as “debris” or “mucin” and missing the brush-border location.
- Giving the diagnosis without suggesting the patient’s immune status is checked.
- Confusing the tiny surface bodies with intracytoplasmic microsporidia or larger Cyclospora/Cystoisospora.
Exam tip: say exactly where the organisms are. “Small round basophilic bodies along the brush border” earns the description mark and makes the diagnosis follow naturally.
Score Yourself
Be honest. Give yourself one score per row, comparing your answer with the model answer above.
Pick one score in each row.
3.5+ very good: correct diagnosis with the key details · 3.0 good: correct with minor omissions · 2.5 adequate (pass): core diagnosis right but incomplete · 2.0 borderline: partly correct, no dangerous error · below 2.0 failing: dangerous misinterpretation or no meaningful answer.
Video Explanation
Watch the case walked through: how to find the organisms, how to word the description, and what the examiner wants to see.
FRCPath Part 2 course
Ultimate FRCPath Part 2 Study Program
This case is one example of how we train for Part 2. The full programme gives you the same format across every system, so the real exam feels familiar.
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