FNCLCC grading of soft tissue sarcomas
Most widely used histologic grading system for adult-type soft tissue sarcomas in Europe (and many MDTs globally).
Used for prognosis, treatment planning, and AJCC staging.
Practical rule: mainly for adult, non–paediatric small round blue cell STS.
Not normally applied to paediatric SRBCTs (Ewing, alveolar RMS, DSRCT) or some special entities.
FNCLCC grading components
| Parameter | Score 1 | Score 2 | Score 3 |
|---|---|---|---|
| Tumour differentiation | Sarcoma closely resembling normal adult mesenchymal tissue / well differentiated | Certain line of differentiation but less obvious, intermediate differentiation | Poorly differentiated or undifferentiated sarcoma |
| Mitotic count (/10 HPF) | 0–9 mitoses | 10–19 mitoses | ≥20 mitoses |
| Tumour necrosis | <50% tumour necrosis | ≥50% tumour necrosis | - |
HPF = standard ×40 objective; actual area is lab-dependent, but for exams just use the cut-offs.
Total Score and Grade
| Total FNCLCC score | FNCLCC Grade |
|---|---|
| 2–3 | Grade 1 |
| 4–5 | Grade 2 |
| 6–8 | Grade 3 |
Clinical Relevance
- Grade 3:
- High risk of metastasis (classically lung) and poorer overall survival.
- Grade is an independent prognostic factor, often more important than size alone.
- Incorporated into AJCC staging and influences:
- Decision for adjuvant radiotherapy / chemotherapy.
- Intensity of follow-up.
Caution / Exceptions
FNCLCC grading is not usually used / not very helpful for:
- GIST → use NIH/AFIP-type risk stratification (size, mitoses, site, rupture).
- Rhabdomyosarcoma (paediatric) → own paediatric risk systems (histologic subtype + stage).
- Ewing sarcoma / PNET and other small round blue cell tumours → generally treated as high-grade by definition.
- Some “special” sarcomas where grading adds little:
- Angiosarcoma, clear cell sarcoma, alveolar soft part sarcoma, epithelioid sarcoma, etc.
