Soft tissue
General
Grading

Author: Komal Arora, M.D. (see Authors page)

Revised: 28 July 2016, last major update July 2012

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Grading [title] soft tissue

Cite this page: Grading. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/softtissuegrading.html. Accessed December 10th, 2016.
Definition / General
  • 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)

  • 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 - grades of common sarcoma types
  • Angiosarcoma-poorly differentiated/epithelioid - 3
  • Angiosarcoma-well differentiated/conventional - 2
  • Chondrosarcoma-mesenchymal - 3
  • Clear cell sarcoma - 3
  • Epithelioid sarcoma - 3
  • Fibrosarcoma-conventional - 2
  • Fibrosarcoma-well differentiated - 1
  • Fibrosarcoma-poorly differentiated - 3
  • Leiomyosarcoma-conventional - 2
  • Leiomyosarcoma-epithelioid / poorly differentiated / pleomorphic - 3
  • Leiomyosarcoma-well differentiated - 1
  • Liposarcoma-myxoid - 2
  • Liposarcoma-pleomorphic - 3
  • Liposarcoma-round cell - 3
  • Liposarcoma-well differentiated - 1
  • Malignant triton tumor - 3
  • MFH-giant cell - 3
  • MFH-pleomorphic with storiform pattern - 2
  • MFH-pleomorphic without storiform pattern - 3
  • Myxofibrosarcoma - 2
  • Osteosarcoma - 3
  • PNET - 3
  • Rhabdomyosarcoma-alveolar / embryonal / pleomorphic - 3
  • Synovial sarcoma – 3

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 - grades of common sarcoma types
National Cancer Institute (US) tumor grading system