Topic Completed: 1 April 2016

Revised: 31 December 2018

Copyright: (c) 2003-2018,, Inc.

PubMed Search: Bone chondrosarcoma dedifferentiated
Page views in 2018: 1,730
Page views in 2019 to date: 718
Cite this page: Stockman DL Chondrosarcoma - dedifferentiated. website. Accessed April 22nd, 2019.
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

Images hosted on PathOut server:

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
Back to top