Inflammatory
Fibroid Polyp
(Eosinophilic Granuloma)
Epidemiology:
- Avg 60s
- Pediatric and
adults
Common sites:
- distal stomach
mostly
- may occur anywhere
in the alimentary tract
Gross features:
- polypoid lesion, sessile or pedunculated
- solitary; rarely
multiple
- well-demarcated
but unencapsulated
- gray-tan
- firm
- smooth or
ulcerated mucosa
Histologic features:
- bulky submucosal growth
- tenuous mucosa
stretched over the surface
- may extend into
mucosa and cause splaying and reactive changes in glands
- may “diffuse
out” / sift through mucosa or muscularis propria
- inflamed, vascular
fibromuscular tissue
- edematous stroma
- bland spindle or
stellate cells mixed with prominent
vasculature and inflammatory cells
- prominent eosinophilic infiltrate
- lymphocytes,
plasma cells, mast cells
- nodular
lymphoid aggregates often
- floret-like
giant cells frequently
- perivascular edema
- cuffing of vessels
and glands by stromal cells
- spindle cells:
- oval or spindle
nuclei
- finely granular
chromatin
- small nucleoli
- eosinophilic cytoplasm
- scarce mitoses
- absent necrosis
Immunophenotype:
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Marker:
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Sensitivity:
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Specificity:
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Vimentin
|
always
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CD34
|
“generally”
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Alpha SMA
|
“
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MSA
|
“
|
|
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CD117 (neg)
|
|
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S100 (neg)
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|
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Desmin (neg)
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Molecular features:
Other features:
- EM - myofibroblastic
- reactive process,
benign
- etiology unknown
- may occlude
pylorus and present as acute gastric outlet obstruction
References:
- Robbins 2005
- Gastrointestinal
and Liver Pathology 2005