GSSE Pathology Summary

Pathology accounts for 25% of the GSSE, covering the mechanisms of disease and their clinical implications across general pathology principles and system-specific disease processes. GSSE pathology questions require more than factual recall — they demand an understanding of underlying mechanisms and the ability to apply pathological concepts to clinical scenarios relevant to surgical practice.

This summary covers the core pathology topics tested in the GSSE, organised by theme, with the depth of knowledge required for exam success.

Cell Injury and Adaptation

Cell injury and adaptation form the foundation of general pathology and appear frequently in GSSE questions, often in the context of explaining clinical or operative findings.

Key topics:

Cell adaptations: hypertrophy, hyperplasia, atrophy, metaplasia, and dysplasia — definitions, stimuli, examples, and clinical significance. Understand the difference between metaplasia (reversible) and dysplasia (pre-neoplastic).
Cell injury mechanisms: ischaemia and reperfusion injury, free radical damage, calcium influx, membrane damage. Reversible vs irreversible injury — when does a cell pass the point of no return?
Types of cell death: necrosis (coagulative, liquefactive, caseous, fat, fibrinoid, gangrenous) vs apoptosis — mechanisms, morphology, and clinical examples. Coagulative necrosis in myocardial infarction; liquefactive necrosis in cerebral infarction and abscess.
Intracellular accumulations: lipids (steatosis), glycogen, protein, pigments (haemosiderin, lipofuscin, melanin, bile), and calcifications (dystrophic vs metastatic).

Inflammation

Inflammation is one of the highest-yield pathology topics in the GSSE. Questions test both the mechanisms of acute and chronic inflammation and their clinical consequences, including wound healing — directly relevant to every surgeon.

Key topics:

Acute inflammation: vascular changes (vasodilatation, increased permeability), cellular events (neutrophil margination, emigration, chemotaxis, phagocytosis), chemical mediators (histamine, prostaglandins, leukotrienes, complement, cytokines — IL-1, TNF, IL-6).
Outcomes of acute inflammation: resolution, suppuration (abscess formation), organisation and fibrosis, chronic inflammation.
Chronic inflammation: mononuclear cell infiltrate (macrophages, lymphocytes, plasma cells), granuloma formation (caseating vs non-caseating), causes, and examples (TB, sarcoidosis, Crohn’s disease, foreign body reaction).
Systemic effects of inflammation: fever (endogenous pyrogens: IL-1, TNF, IL-6), acute phase response (CRP, fibrinogen, complement), leucocytosis, and the physiological basis of SIRS and sepsis.

Wound Healing

Wound healing is directly applicable to surgical practice and is consistently tested in the GSSE. Candidates must understand both the mechanisms and the factors that impair healing.

Key topics:

Phases of wound healing: haemostasis (platelet plug, coagulation cascade), inflammation (neutrophil then macrophage predominance), proliferation (fibroblasts, angiogenesis, re-epithelialisation), and remodelling (collagen maturation, wound contraction, tensile strength).
Healing by primary vs secondary intention: mechanisms, timelines, and clinical implications.
Collagen: types I and III, role in wound strength, crosslinking, and maturation. Tensile strength returns to ~80% of original — never fully recovers.
Factors impairing wound healing: local (infection, ischaemia, foreign body, excessive movement, radiation) and systemic (malnutrition/vitamin C deficiency, corticosteroids, diabetes, immunosuppression, zinc deficiency, anaemia, age).
Abnormal healing: keloid vs hypertrophic scar (extends beyond wound margins vs stays within), dehiscence, incisional hernia, contracture.

Neoplasia

Neoplasia is a major pathology topic in the GSSE, tested both at the cellular/molecular level and in the context of the clinical behaviour of tumours.

Key topics:

Benign vs malignant tumours: growth rate, invasion, metastasis, differentiation, nuclear morphology, mitotic activity. Know the naming conventions for benign and malignant tumours from different cell types.
Carcinogenesis: oncogenes (gain of function), tumour suppressor genes (loss of function — two-hit hypothesis), DNA repair genes, and the multistep model of cancer development.
Important oncogenes and tumour suppressors: RAS, MYC, HER2/ERBB2 (oncogenes); TP53, RB1, APC, BRCA1/2 (tumour suppressors) — know which cancers they are associated with.
Tumour spread: direct invasion, lymphatic spread (most common route for carcinomas), haematogenous spread (most common route for sarcomas), transcoelomic spread. Common sites of metastasis for common cancers (lung, liver, bone, brain, adrenal).
Tumour grading and staging: grading = histological differentiation (G1–G3); staging = extent of spread (TNM system). Staging is the stronger predictor of prognosis.
Paraneoplastic syndromes: SIADH, Cushing syndrome, hypercalcaemia (PTHrP), Lambert-Eaton syndrome, acanthosis nigricans — tumours of origin.
Tumour markers: CEA (colorectal), AFP (hepatocellular, germ cell), PSA (prostate), CA-125 (ovarian), CA 19-9 (pancreatic) — use and limitations.

Haemodynamics and Thrombosis

Haemodynamics and thrombosis are fundamental to surgical pathology, underpinning the understanding of venous thromboembolism, ischaemia, and haemorrhagic complications.

Key topics:

Virchow’s triad: endothelial injury, hypercoagulability, stasis — understand how each contributes to thrombosis in surgical patients.
Arterial vs venous thrombi: composition (platelet-rich “white thrombus” vs fibrin-rich “red thrombus”), sites, and consequences.
Embolism: pulmonary embolism (source, consequences, V/Q mismatch, saddle embolus), fat embolism, air embolism, amniotic fluid embolism — mechanisms and clinical features.
Ischaemia and infarction: end arteries vs collateral supply, red (haemorrhagic) vs pale infarcts, reperfusion injury.
Oedema: pathophysiological mechanisms — increased hydrostatic pressure, decreased oncotic pressure (hypoalbuminaemia), lymphatic obstruction, sodium retention, increased vascular permeability.
Shock: hypovolaemic, cardiogenic, distributive (septic, anaphylactic, neurogenic), obstructive — mechanisms and end-organ consequences. Progression from compensated to decompensated shock.
Disseminated intravascular coagulation (DIC): triggers, pathophysiology (consumption of clotting factors and platelets, fibrin microthrombi), laboratory findings, and management principles.

Immunopathology

Immunopathology in the GSSE covers hypersensitivity reactions, autoimmunity, and transplant rejection — all relevant to surgical patients.

Key topics:

Hypersensitivity reactions (Gell and Coombs classification):
- Type I (immediate/IgE-mediated): anaphylaxis, atopy
- Type II (antibody-mediated cytotoxicity): haemolytic transfusion reactions, Goodpasture’s disease
- Type III (immune complex-mediated): serum sickness, SLE, post-streptococcal glomerulonephritis
- Type IV (delayed/cell-mediated): contact dermatitis, TB, transplant rejection
Transplant rejection: hyperacute (preformed antibodies), acute (T-cell mediated), and chronic rejection (antibody-mediated vasculopathy). Immunosuppression in transplant patients.
Autoimmune diseases with surgical relevance: Graves’ disease, Hashimoto’s thyroiditis, primary sclerosing cholangitis, Crohn’s disease, ulcerative colitis.

Microbiology and Infection

The microbiology component of GSSE pathology focuses on surgically relevant infections, wound infections, and the principles of antimicrobial therapy.

Key topics:

Gram-positive organisms: Staphylococcus aureus (including MRSA — cell wall-active antibiotics fail), Staphylococcus epidermidis (biofilm), Streptococcus pyogenes (necrotising fasciitis), Clostridium species (gas gangrene, C. difficile).
Gram-negative organisms: Escherichia coli, Klebsiella, Pseudomonas aeruginosa, Bacteroides — anaerobes in abdominal sepsis.
Surgical site infections: classification (superficial, deep, organ/space), common organisms by site, prevention strategies.
Sepsis: definitions (SIRS, sepsis, septic shock), pathophysiology (endotoxin, cytokine cascade, vasodilatation, distributive shock), and management principles.
Antibiotic mechanisms: cell wall synthesis (beta-lactams, vancomycin), protein synthesis (aminoglycosides, macrolides, tetracyclines), DNA replication (fluoroquinolones), folate synthesis (trimethoprim). Mechanisms of resistance.
Fungal infections: Candida in surgical patients (risk factors, treatment), Aspergillus in immunocompromised hosts.

Pathology of Common Surgical Conditions

Beyond general pathology principles, the GSSE tests the pathological basis of common surgical diseases.

Key conditions:

Atherosclerosis: risk factors, pathogenesis (endothelial injury → lipid accumulation → foam cells → fibrous cap → plaque instability → thrombosis), complications, and clinical manifestations.
Colorectal cancer: adenoma-carcinoma sequence, APC mutation, Duke’s and TNM staging, Lynch syndrome (MMR gene mutations).
Peptic ulcer disease: role of H. pylori, NSAID-induced mucosal injury, Zollinger-Ellison syndrome, complications (haemorrhage, perforation, obstruction).
Appendicitis: pathology of acute appendicitis, perforation, and peritonitis.
Pancreatitis: causes (gallstones, alcohol), pathophysiology of acinar cell injury, local and systemic complications.
Liver pathology: hepatic cirrhosis — causes, consequences (portal hypertension, varices, ascites, hepatic encephalopathy, coagulopathy, hepatorenal syndrome).

How to Study GSSE Pathology Effectively

Pathology rewards candidates who understand mechanisms rather than those who memorise facts. Every pathological process has a logical sequence from trigger to consequence — understanding that sequence allows you to answer questions you have never seen before.

Effective pathology preparation strategies:

Work through question-based practice by topic, reviewing explanations in detail for every question
For each disease or process, work through: cause → mechanism → morphological changes → clinical presentation → complications
Link pathology to physiology — many questions require integration of both
Focus heavily on inflammation, neoplasia, and haemodynamics — the highest-yield general pathology areas
Cover surgically relevant system pathology, particularly colorectal, hepatobiliary, and vascular disease

Prepare with GSSEPrep

GSSEPrep provides a comprehensive pathology question bank structured by topic and aligned to the GSSE syllabus, with detailed explanations and textbook references for every question. Performance tracking identifies weak areas across general and system pathology so you can focus your preparation efficiently.