Soft tissue
Fibroblastic / myofibroblastic tumors
Ischemic fasciitis

Author: Ali Chaudhri, M.D. (see Authors page)
Editor: Jerad M. Gardner, M.D.

Revised: 26 August 2016, last major update June 2013

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

PubMed Search: Ischemic fasciitis

Definition / General
  • Painless pseudosarcomatous fibroblastic proliferation in soft tissue overlying bony prominences subject to intermittent pressure-induced ischemia
  • Also spelled "ischaemic"
  • First described in 1992 as "atypical decubital fibroplasia" (Am J Surg Pathol 1992;16:708)
Epidemiology
Sites
  • Shoulder, chest wall, sacrococcygeal region, greater trochanter
Etiology
  • Similar to decubitus ulcers; pressure-induced ischemia causes mass-producing reactive process, but is insufficient to cause skin ulceration
Case Reports
Treatment
  • Local excision is curative, although may recur due to continuation of underlying ischemia and injury
Clinical Images

Images hosted on PathOut servers:

Decubital, courtesy of
Mark R. Wick, M.D.

Gross Description
  • Usually 1 - 8 cm, poorly circumscribed, often myxoid
  • Usually involves deep subcutis, may involve adjacent skeletal muscle and fascia
  • Ulceration is uncommon (i.e. overlying skin is intact)
Micro Description
  • Zonal pattern of central fibrinoid necrosis with uneven borders staining deep red / violet and prominent myxoid areas surrounded by ectatic, thin walled vessels and proliferating fibroblasts
  • Endothelial cells may be atypical
  • Fibroblasts have degenerative features with abundant, eosinophilic to amphophilic cytoplasm, enlarged nuclei with smudged chromatin and prominent nucleoli (resembling ganglion-like cells in proliferative fasciitis)
  • Variable mitotic activity, but no atypical mitotic figures
  • Fibrin thrombi are common within peripheral vessels, which may show fibrinoid necrosis and recanalization but no true vasculitis
  • May have multivacuolated macrophages in myxoid zones mimicking lipoblasts
Micro Images

Images hosted on PathOut servers:

Decubital, courtesy of Mark R. Wick, M.D.

Cellular, fibrin-rich proliferation centered on subcutaneous fibrous septum and extending into adjacent fat

Hyalinized focus with large ganglion-like cells, suggestive of proliferative fasciitis

Fibrin is adjacent to foci of ganglion-like cells in collagenous stroma




Case of the Week #64 - Hip mass in 55 year old bedridden man



Images hosted on other servers:

Fibrinoid necrosis with few viable cells

Large nuclei with prominent nucleoli

Various images

Cytology Description
Positive Stains
Negative Stains
Differential Diagnosis
  • Epithelioid sarcoma: young adults on distal extremities, more cellular with central tumor cell necrosis, cells have eosinophilic cytoplasm, atypical mitotic figures, keratin+
  • Myxofibrosarcoma: marked atypia, but no smudgy chromatin or fibrin thrombi; lacks zonation and degenerative features
  • Myxoid liposarcoma: prominent plexiform vasculature and lipoblasts, small monotonous cells rather than larger myofibroblasts
  • Proliferative fasciitis: younger patients, lesions not associated with pressure; zonation, myofibroblasts and fibroblasts with tissue culture type growth, also large ganglion cells