Soft tissue
Fibrohistiocytic tumors
Atypical fibrous histiocytoma

Author: Vijay Shankar, M.D. (see Authors page)

Revised: 13 September 2016, last major update August 2012

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Atypical fibrous histiocytoma

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
Terminology
  • 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)
Epidemiology
  • Median age 38 years (range 5 - 90 years), no gender preference
Sites
Case Reports
Treatment
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
Micro 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
Micro 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