Inflammatory fibroid polyp: an immunohistochemical study

Arq Gastroenterol. Apr-Jun 2004;41(2):104-7. doi: 10.1590/s0004-28032004000200007. Epub 2004 Oct 27.


Background: Inflammatory fibroid polyp is a localized lesion, which arises in the submucosa of the gastrointestinal tract, most often in the stomach. Although it is generally believed to represent a reactive, nonneoplastic condition, its histogenesis remains controversial.

Aim: To study inflammatory fibroid polyp by immunohistochemistry in an attempt to further clarify their histogenesis.

Material and methods: Nine cases were studied by immunohistochemistry using a panel of antibodies against smooth-muscle actin, vimentin, S-100 protein, factor VIII- R.Ag and macrophage (HAM-56).

Results: There was a strong diffuse positive staining pattern in the spindle cells with vimentin antibody. A patchy staining for smooth-muscle actin was observed in these cells. Immunophenotyping revealed a heterogeneous reaction with HAM-56. In edematous areas, HAM-56-positive cells show voluminous cytoplasm and reniform nuclei. In cell-rich areas, the HAM-56-positive cells had fusiform cytoplasm. Stains for S-100 and factor VIII RAg were negative in the proliferating elements.

Conclusions: The present immunohistochemical study refutes the suggested neural or vascular nature of the lesion. The strong positivity for vimentin in all cases suggests a major component of spindle cells best recognizable as fibroblasts. These results would favor the existence of a span of morphological and immunohistochemical patterns possibly indicating evolutive phases of an inflammatory reaction.

MeSH terms

  • Adult
  • Female
  • Fibroblasts / pathology
  • Gastrointestinal Neoplasms / chemistry
  • Gastrointestinal Neoplasms / pathology*
  • Humans
  • Immunohistochemistry
  • Intestinal Mucosa / chemistry
  • Intestinal Mucosa / pathology
  • Intestinal Polyps / chemistry
  • Intestinal Polyps / pathology*
  • Male
  • Middle Aged
  • Vimentin / analysis


  • Vimentin