Soft tissue
General
Grading
Topic Completed: 1 July 2012
Minor changes: 14 September 2020
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PubMed Search: Grading [title] soft tissue
Cite this page: Arora K. Grading. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/softtissuegrading.html. Accessed April 19th, 2021.
Definition / general
- The primary reference for grading is Fletcher: WHO Classification of Tumours of Soft Tissue and Bone (IARC, 2013); see also Cancer 1986;58:306
- Indicate in pathology report which grading system is used
- Grade is most important prognostic factor and indicator of metastatic risk in adults (Arch Pathol Lab Med 2006;130:1448)
- Note: Grading of malignant peripheral nerve sheath tumor, embryonal and alveolar rhabdomyosarcoma, angiosarcoma, extraskeletal myxoid chondrosarcoma, alveolar soft part sarcoma, clear cell sarcoma and epithelioid sarcoma is not recommended; the case for grading malignant peripheral nerve sheath tumor is currently being debated (modified with permission from Coindre, Arch Pathol Lab Med 2006;130:1448)
- More information is available on the CAP Cancer Protocol page
- Note: see the bottom of the Soft Tissue chapter Table of Contents for staging information
- Two grade systems - low grade and high grade:
- Low grade: usually has limited ability to metastasize
- High grade: cellular with mitotic figures and necrosis, but must evaluate in context of tumor type, age and location
- For example: superficial high grade MFH is unlikely to metastasize, but deep low grade MPNST is likely to metastasize
- Necrosis usually signifies high grade unless tumor is well differentiated and lacks pleomorphism
Grading
French Federation of Cancer Centers Sarcoma Group
French Federation of Cancer Centers Sarcoma Group - Tumor Differentiation Score by Histologic Type
Notes:
National Cancer Institute (US) tumor grading system
- Grades:
- Grade 1: total score of 2 - 3 points
- Grade 2: total score of 4 - 5 points
- Grade 3: total score of 6 - 8 points
- Tumor differentiation:
- 1 point: resembles normal adult mesenchymal tissue, may be confused with a benign lesion, such as well differentiated liposarcoma
- 2 points: histologic typing is certain, such as myxoid liposarcoma
- 3 points: synovial sarcoma, osteosarcoma, Ewing’s sarcoma / PNET, sarcomas of doubtful tumor type, embryonal and undifferentiated sarcomas
- Mitotic count (count 10 successive high power fields [area of 0.17 mm squared] in most mitotically active areas):
- 1 point: 0 - 9 mitoses
- 2 points: 10 - 19 mitoses
- 3 points: 20 or more mitoses
- Tumor necrosis:
- 0 points: no necrosis on any slides
- 1 point: less than 50% necrosis for all examined tumor surface
- 2 points: tumor necrosis of 50% or more of examined tumor surface
French Federation of Cancer Centers Sarcoma Group - Tumor Differentiation Score by Histologic Type
| Histologic type | Score |
| Atypical lipomatous tumor / well differentiated liposarcoma | 1 |
| Well differentiated leiomyosarcoma | 1 |
| Malignant neurofibroma | 1 |
| Well differentiated fibrosarcoma | 1 |
| Myxoid liposarcoma | 2 |
| Conventional leiomyosarcoma | 2 |
| Conventional fibrosarcoma | 2 |
| Myxofibrosarcoma | 2 |
| High grade myxoid (round cell) liposarcoma | 3 |
| Pleomorphic liposarcoma | 3 |
| Dedifferentiated liposarcoma | 3 |
| Pleomorphic rhabdomyosarcoma | 3 |
| Poorly differentiated / pleomorphic leiomyosarcoma | 3 |
| Biphasic / monophasic / poorly differentiated synovial sarcoma | 3 |
| Mesenchymal chondrosarcoma | 3 |
| Extraskeletal osteosarcoma | 3 |
| Extraskeletal Ewing sarcoma | 3 |
| Malignant rhabdoid tumor | 3 |
| Undifferentiated pleomorphic sarcoma | 3 |
| Undifferentiated sarcoma, not otherwise specified | 3 |
Notes:
- Grading of malignant peripheral nerve sheath tumor, embryonal and alveolar rhabdomyosarcoma, angiosarcoma, extraskeletal myxoid chondrosarcoma, alveolar soft part sarcoma, clear cell sarcoma and epithelioid sarcoma is not recommended (Cancer 1984;53:530)
- The case for grading malignant peripheral nerve sheath tumor is currently being debated
- Modified with permission from Coindre JM (Arch Pathol Lab Med 2006;130:1448)
National Cancer Institute (US) tumor grading system
- Grade 1:
- Well differentiated liposarcoma
- Myxoid liposarcoma (grade 2 in French system above)
- Subcutaneous myxoid MFH
- Well differentiated malignant hemangiopericytoma with < 1 MF / 10 HPF, no necrosis and no hemorrhagic areas
- Well differentiated fibrosarcoma with orderly herringbone pattern or well differentiated leiomyosarcoma with orderly fascicular pattern plus well differentiated cytologic features, no pleomorphism, no necrosis, < 6 MF / 10 HPF
- Malignant schwannoma (MPNST) if resembles neurofibroma plus mitotic figures plus areas of high cellularity but < 6 MF / 10 HPF
- Myxoid chondrosarcoma that is uniformly myxoid and hypocellular with no mitotic activity
- Grade 2:
- Other histologic types with < 15% necrosis
- Grade 3:
- Extraskeletal Ewing’s sarcoma, PNET, extraskeletal osteosarcoma, mesenchymal chondrosarcoma, malignant triton tumor, or other histologic types with 15% or more necrosis
Additional references
French Federation of Cancer Centers Sarcoma Group - Tumor Differentiation Score by Histologic Type
National Cancer Institute (US) tumor grading system
- Fletcher: WHO Classification of Tumours of Soft Tissue and Bone (Medicine), 4th Edition, 2013, Arch Pathol Lab Med 2006;130:1448, Pathol Int 2007;57:121, Cancer 1986;58:306
National Cancer Institute (US) tumor grading system
