Bone & joints

Other tumors

Undifferentiated pleomorphic sarcoma

Topic Completed: 1 June 2005

Minor changes: 23 June 2020

Copyright: (c) 2003-2019,, Inc.

PubMed search: malignant fibrous histiocytoma [title] bone

Nat Pernick, M.D.
Page views in 2020: 881
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Cite this page: Pernick N Undifferentiated pleomorphic sarcoma. website. Accessed October 25th, 2021.
Definition / general
  • Mean age 34 - 40 years but all ages, no gender predominance
  • Sites: metaphysis of long bones, jaw
  • Associated with bone infarcts (30%), foreign bodies, radiation (15%, Am J Surg Pathol 1986;10:9), Paget disease, dedifferentiation or transformation of chondrosarcoma, chordoma or giant cell tumor
  • Behaves like a high grade sarcoma with a poor prognosis, particularly for older patients and secondary sarcomas
  • Five year survival of 78% if prominent chronic inflammatory infiltrate
Radiology images

Radiograph of tibial tumor

Contributed by Dr. Mark R. Wick

Primary, distal femur

Gross images

Contributed by Dr. Mark R. Wick


Microscopic (histologic) images

Mixture of malignant fibroblasts and histiocytes

Fibroblasts dominate

Irregular deposits of noncalcified collagen

Broad area of collagen deposits is sparsely cellular

Markedly vascular tumor

Contributed by Dr. Mark R. Wick


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