Soft tissue

So called fibrohistiocytic

Plexiform fibrohistiocytic tumor

Last author update: 1 August 2012
Last staff update: 9 November 2021

Copyright: 2003-2023,, Inc.

PubMed Search: Plexiform fibrohistiocytic tumor [title] soft tissue

Vijay Shankar, M.D.
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Cite this page: Shankar V. Plexiform fibrohistiocytic tumor. website. Accessed June 8th, 2023.
Definition / general
  • Dermal or subcutaneous, plexiform or multinodular proliferation of fibrohistiocytic cells and osteoclast-like giant cells with chronic inflammatory infiltrate
  • Usually children and young adults, 80% female
Clinical features
Case reports
Gross description
  • Multinodular, poorly circumscribed, firm, dermal or subcutaneous, 3 cm or less
Microscopic (histologic) description
  • Deep dermal or subcutaneous tumor with ray like extension into skeletal muscle or adipose tissue
  • Overlying epidermis and dermis are usually normal
  • Plexiform or multinodular proliferation of fibrohistiocytic cells with minimal atypia plus osteoclast-like giant cells and chronic inflammatory infiltrate
  • Nodules or clusters are interconnected in characteristic plexiform arrangement
  • Prominent dilated vessels; more sclerotic than MFH
  • Often hemorrhage and hemosiderin
  • Vascular invasion in 10 - 20%
  • Usually 0 - 2 MF / 10 HPF, no necrosis
  • Subtypes are fibrohistiocytic (histiocyte-like cells and giant cells), fibroblastic (fibroblast-like cells) and mixed
Microscopic (histologic) images

AFIP images

Subcutaneous proliferation of bland fibrous tissue which radiates outward from center of lesion

Tumors have nodules of histiocyte-like cells
and giant cells, fibrous tissue and hemorrhage

Histiocyte-like cells, pale staining cytoplasm; giant cells present

Nodules may be composed of cells w/ elongated nuclei

Tumor with nodules and fibrous tissue

Fibrous tissue may resemble desmoid fibromatosis

Contributed by Mark R. Wick, M.D.

Various images

Case #180

Images hosted on other servers:

Various images

12 year old girl with upper arm lesion

Cytology description
  • Plump fibroblastic cells and histiocyte-like cells within a finely granular myxoid background
  • Also osteoclast-like giant cells (Acta Cytol 1999;43:867)
Positive stains
Negative stains
Electron microscopy description
  • Resembles myofibroblasts, fibroblasts and undifferentiated cells
Differential diagnosis
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