Bone & joints
Dedifferentiated chondrosarcoma

Topic Completed: 1 April 2016

Minor changes: 4 July 2020

Copyright: 2003-2019,, Inc.

PubMed Search: Bone chondrosarcoma dedifferentiated

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Cite this page: Stockman DL. Dedifferentiated chondrosarcoma. website. Accessed March 9th, 2021.
Definition / general
  • High grade malignant neoplasm composed of a well differentiated cartilaginous tumor, usually low grade conventional chondrosarcoma, with either high grade pleomorphic, undifferentiated pleomorphic (UPS) or spindle cell sarcoma like areas
  • Less frequently originates as an enchondroma or osteochondroma, in patients with hereditary exostosis
  • Bimodal age distribution; patients with exostosis may develop chondrosarcomas earlier in life
  • Poor prognosis, with 5 year survival of 10% to 35% (pelvis)
Radiology description
  • Low grade component manifests as mineralized area with rings and arcs
  • High grade component is lytic and aggressive, with permeation and destruction of underlying bone
  • Wide excision and systemic therapy, although the latter seems to be relatively ineffective
  • Many patients are older and have medical conditions limiting tolerance to therapy
Radiology images

AFIP images

Cartilaginous matrix

Contributed by Dr. Mark R. Wick
Gross description
  • Cartilage tumor adjacent to fish-flesh appearance of sarcoma
Gross images

Contributed by Dr. Mark R. Wick

Various images

Microscopic (histologic) description
  • Conventional chondrosarcoma juxtaposed to high grade pleomorphic or spindle cell sarcoma
  • May have features of angiosarcoma, clear cell chondrosarcoma, fibrosarcoma, osteosarcoma, rhabdomyosarcoma, squamous cell carcinoma
Microscopic (histologic) images

Contributed by Dr. Mark R. Wick

Various images

AFIP images

Low grade cartilaginous neoplasm

Pulmonary metastases

Images hosted on other servers:

Dedifferentiated chondrosarcoma

UPMC Case #118

Positive stains
  • IDH1 and IDH2 overexpression
  • SOX9 identifies chondrogenic differentiation, particularly useful in high grade areas seen on biopsy without sampled cartilaginous areas
  • p53 overexpression, although not useful in practice
Differential diagnosis
  • Chondroblastic osteosarcoma: young patients; gradual transition from high grade cartilaginous tumor to spindle cell sarcoma
  • High grade spindle cell sarcoma / undifferentiated pleomorphic sarcoma of bone
  • Metastatic sarcomatoid carcinoma
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