Inflammatory Fibroid Polyp
Differential Diagnosis
- GIST
- Solitary fibrous tumor
- Schwannoma
- Inflammatory myofibroblastic tumor
- Perineurioma
- Leiomyoma
- Gastric plexiform fibromyxoma
| Inflammatory Fibroid Polyp | GIST (spindled, bland) |
| Submucosal | Intramural |
| Spindled and stellate cells | Spindled but no stellate cells |
| Abundant stromal eosinophils | Eosinophils infrequent |
| Perivascular concentric cuffing common | Lacks concentric cuffing |
| Fibromyxoid background with regular vascular pattern | May be myxoid but lacks regular vascular pattern |
| CD117 negative | CD117 74-95% |
| DOG1negative | DOG1 87-94% |
Submucosal |
In GI tract, arises in serosa |
Regular small to medium size vascular pattern |
HPC-like vessels common |
Fibromyxoid stroma |
Ropy collagen |
Eosinophil rich inflammatory stroma |
Inflammation infrequent |
| Inflammatory Fibroid Polyp | GI Schwannoma |
| Eosinophil rich inflammatory infiltrate throughout | Peripheral lymphoid cuff common |
| Perivascular concentric cuffing common, palisading rare | May palisade, no concentric pattern |
| Fibromyxoid background with regular vascular pattern | May be myxoid but lacks regular vascular pattern |
| S100 negative | S100 100% |
| Inflammatory Myofibroblastic Tumor | Inflammatory Fibroid Polyp |
| Usually in children | Rare in children |
| Frequently associated with systemic signs and symptoms | Not associated with systemic signs and symptoms |
| Plasma cells > eosinophils | Eosinophils > plasma cells |
| Frequently positive for desmin, keratin and ALK | Desmin, keratin and ALK negative |
| Nuclear pleomorphism frequent | Cytologically bland |
| Lacks regular vascular pattern | Regular vascular pattern |
| May have necrosis and calcification | Necrosis and calcification rare |
| CD34 negative | CD34 80-90% |
| Inflammatory Fibroid Polyp | GI Perineurioma |
| Submucosal | Predominantly lamina propria |
| Eosinophil rich inflammatory infiltrate | Eosinophils and inflammation infrequent |
| Perivascular concentric cuffing common | Lacks prominent concentric cuffing |
| Fibromyxoid background with regular vascular pattern | Rarely may be myxoid but lacks regular vascular pattern |
| CD34 positive in 80% | CD34 weak focal in 15-30% |
| Inflammatory Fibroid Polyp | Leiomyoma |
| Desmin negative | Desmin positive |
| Spindled and stellate cells | Spindled but no stellate cells |
| Abundant stromal eosinophils | Eosinophils infrequent |
| Perivascular concentric cuffing common | Lacks concentric cuffing |
| Fibrous or myxoid background | May be myxoid but usually no fibrous background |
| Inflammatory Fibroid Polyp | Gastric Plexiform Fibromyxoma |
| Usually solitary nodule | Multinodular, plexiform |
| Usually a pedunculated polyp | Intramural |
| Centered on submucosa | Centered on muscularis propria |
| Frequent inflammatory infiltrate | No intrinsic inflammatory infiltrate |
| May have concentric perivascular pattern of spindle cells | Lacks concentric pattern |
| CD34 frequently positive | CD34 negative |
