Soft tissue
Fibrohistiocytic tumors
Atypical fibrous histiocytoma

Topic Completed: 1 August 2012

Minor changes: 22 March 2019

Copyright: 2002-2018,, Inc.

PubMed Search: Atypical fibrous histiocytoma

Vijay Shankar, M.D.
Page views in 2019: 5,095
Page views in 2020 to date: 1,822
Cite this page: Shankar V. Atypical fibrous histiocytoma. website. Accessed May 29th, 2020.
Definition / general
  • Cellular, circumscribed dermal lesion of spindled fibroblasts, myofibroblasts, histiocyte-like cells and often giant cells
  • Marked nuclear pleomorphism and mitotic figures (often atypical)
  • No tumor cell necrosis
  • No vascular invasion
  • Rare variant of cutaneous fibrous histiocytoma
  • Also called pseudosarcomatous fibrous histiocytoma or dermatofibroma with monster cells
  • Part of WHO classification for skin tumors, not soft tissue tumors
  • First described in 1983 (J Cutan Pathol 1983;10:327)
  • Median age 38 years (range 5 - 90 years), no gender preference
Case reports
Clinical images

Images hosted on other servers:

Exophytic nodular lesion of abdominal wall

Gross description
  • Median 1.5 cm (0.4 to 8 cm), nodular or polypoid
Microscopic (histologic) description
  • Involvement of dermis and superficial subcutaneous tissue by pleomorphic, plump, spindle or polyhedral cells with large hyperchromatic, irregular or bizarre nuclei
  • Background of classic fibrous histiocytoma including epidermal hyperplasia, Grenz zone, spindle cells with storiform pattern and entrapped thick collagen bundles, especially at periphery
  • Variable multinucleated giant cells, often with bizarre nuclei (monster cells, Am J Dermatopathol 1987;9:380) and foamy or hemosiderin-rich cytoplasm
  • Mild to marked pleomorphism
  • 0 - 15 mitotic figures / 10 HPF, frequently atypical
  • Necrosis occasionally present
Microscopic (histologic) images

Images hosted on PathOut servers:

Enlarged cells with hyperchromatic nuclei, but no / rare mitotic figures (source: AFIP Fascicle, 3rd series)

Positive stains
Negative stains
Differential diagnosis
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