On gross examination, IF tumors are typically white-yellow masses with central necrosis (i.e. areas of dead or dying cells), and areas containing cysts and/or old, dried hemorrhages. The tumors are often poorly circumscribed, have an infiltrative appearance, may be multinodular, and lie in subcutaneous tissue but may also involve the dermal layer of the skin and/or the reticular dermis. Microscopic histopathological studies of IF tissues report the characteristic presence of a distinct zonal appearance, i.e. the presence of central zones of fibrinoid necrosis and areas of cyst-laden necrosis in a hypocellular background surrounding by a zone of granulation tissue (i.e. connective tissue containing microscopic blood vessels) populated by atypical, swollen fibroblasts, myofibroblasts, and/or macrophages. Immunohistochemistry analyses of IF tumors often show the presence of fibroblasts, fibroblast-like cells, and or other types of cells that in a percentage of cases express smooth muscle actin proteins, CD68 protein,. desmin protein, vimentin protein, and collagen type IV protein, but not keratin, S100, calponin, or CD34 proteins. The finding that a tumor's cells have some of these patterns of protein expression can help support the diagnosis of IF.
Ischemic fasciitis
Plantar fasciitis
Necrotizing fasciitis
Anterior compartment syndrome
Eosinophilic fasciitis
Heel pad syndrome
Fasciitis
Osteoradionecrosis