RCC WHO/ISUP Grading
Feature-checklist WHO/ISUP nucleolar grading (G1–G4) for renal cell carcinoma, with full reasoning shown.
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This calculator is a pathology decision-support and educational tool for applying the WHO/ISUP nucleolar grading system. It does not replace professional pathologist judgment, institutional protocols, or the current edition of the applicable classification.
Reference
Table 1.03 — WHO/ISUP grading system for clear cell RCC and papillary RCC
The scale is a nested magnification threshold. Grades 1–3 track the lowest magnification at which nucleoli become conspicuous and eosinophilic — the lower the magnification needed to see them prominently, the higher the grade (up to Grade 3). Grade 4 is a separate, qualitative override based on nuclear pleomorphism and differentiation features, independent of nucleolar prominence.
| Grade | Description |
|---|---|
| Grade 1 | Nucleoli are absent or inconspicuous and basophilic at ×400 magnification. |
| Grade 2 | Nucleoli are conspicuous and eosinophilic at ×400 magnification and visible but not prominent at ×100 magnification. |
| Grade 3 | Nucleoli are conspicuous and eosinophilic at ×100 magnification. |
| Grade 4 | There is extreme nuclear pleomorphism, multinucleate giant cells, and/or rhabdoid and/or sarcomatoid differentiation. |
Scope
This WHO/ISUP system applies to clear cell and papillary renal cell carcinoma specifically, as titled in the source table. Other RCC subtypes may use different grading criteria, or none.
Source
Table 1.03, WHO/International Society of Urological Pathology (ISUP) grading system for clear cell renal cell carcinoma and papillary renal cell carcinoma, as reproduced from the WHO Classification of Tumours (reference marker {677} in the source table was not resolvable to a full citation from the supplied image and is not fabricated here).