WHO Classification of Tumours (5th ed.)
The international reference that defines and names tumours, integrating histopathology with molecular pathology.
The international standard that integrates histopathology with molecular pathology to define and name tumours.
What it is
The WHO Classification of Tumours, often called the “WHO Blue Books”, is the internationally recognised reference series published by the International Agency for Research on Cancer (IARC) under the World Health Organization. Each volume classifies the tumours of a particular organ system and defines how each entity is named, diagnosed and graded.
Why it matters
It gives pathologists, oncologists and laboratories a common diagnostic language, so that a diagnosis carries the same meaning across hospitals, cities and countries. The 5th edition increasingly integrates molecular and genetic findings alongside traditional microscopy, reflecting how modern diagnosis combines histopathology, immunohistochemistry and molecular pathology.
Key points
- Organised by organ system across a series of volumes (the “Blue Books”)
- Defines standard tumour nomenclature, diagnostic criteria and grading
- Integrates morphology with immunohistochemistry and molecular findings
- Updated across editions to include newly recognised tumour entities
How our reporting uses it
Our histopathology and molecular reports are structured to align with current WHO terminology and criteria, so that referring clinicians receive diagnoses in a form consistent with international practice.
Keep reading
Related department: Histopathology · Molecular Diagnostics
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