Inflammatory fibroid polyp
This non-neoplastic lesion occurs throughout the gastrointestinal tract in adults of all ages, but in the small intestine (most frequently in the terminal ileum) more commonly forms a symptomatic mass causing obstruction by intussusception. The polyps usually measure 1–5 cm and are often pedunculated and project intraluminally, appearing greywhite and glistening on sectioning. Mucosal ulceration is possible. The histologically typical appearance is oedematous with spindled to epithelioid tumour cells admixed with eosinophilic granulocytes and histiocytes and a prominent capillary network. In a minority of cases, the tumour cells are (focally) positive for CD34 and SMA. They are negative for KIT and DOG1, but positive for PDGFRA. PDGFRA-activating mutations (especially in exon 12) resembling those seen in gastrointestinal stromal tumours (GISTs) are present in > 50% of cases
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Gain-of-function PDGFRA mutations, earlier reported in gastrointestinal stromal tumors, are common in small intestinal inflammatory fibroid polyps. A study of 60 cases.
Mod Pathol 22: 1049-56
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. Similar mutations also occur in gastric inflammatory fibroid polyps
Inflammatory fibroid polyps of the intestine.
Am J Clin Pathol 81: 708-14
Schildhaus HU, Cavlar T, Binot E, Büttner R, Wardelmann E, Merkelbach-Bruse S (2008)
Inflammatory fibroid polyps harbour mutations in the platelet-derived growth factor receptor alpha (PDGFRA) gene.
J Pathol 216: 176-82
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WHO Classification of Tumours of the Digestive System.
International Agency for Research on Cancer: Lyon 2010