Bone & joints

Undifferentiated small round cell sarcoma of bone and soft tissue

Undifferentiated pleomorphic sarcoma



Last author update: 1 June 2005
Last staff update: 28 January 2022

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PubMed search: malignant fibrous histiocytoma [title] bone

Nat Pernick, M.D.
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Cite this page: Pernick N Undifferentiated pleomorphic sarcoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/boneMFH.html. Accessed February 8th, 2023.
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%), Paget disease, dedifferentiation or transformation of chondrosarcoma, chordoma or giant cell tumor (Am J Surg Pathol 1986;10:9)
  • 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

Contributed by AFIP images and Mark R. Wick, M.D.

Radiograph of tibial tumor

Primary, distal femur

Gross images

Contributed by Mark R. Wick, M.D.

Primary

Microscopic (histologic) images

Contributed by AFIP images and Mark R. Wick, M.D.

Mixture of malignant fibroblasts and histiocytes

Fibroblasts dominate

Irregular deposits of noncalcified collagen

Broad area of collagen deposits is sparsely cellular


Markedly vascular tumor

Various images

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