Soft tissue
General
Grading


Topic Completed: 1 July 2012

Revised: 29 October 2019

Copyright: 2002-2019, PathologyOutlines.com, Inc.

PubMed Search: Grading [title] soft tissue

Komal Arora, M.D.
Farres Obeidin, M.D.
Page views in 2018: 8,657
Page views in 2019 to date: 9,412
Cite this page: Arora K. Grading. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/softtissuegrading.html. Accessed December 8th, 2019.
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
  • 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
Back to top