Surgical Pathology Criteria

Inflammatory Fibroid Polyp

Differential Diagnosis

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%
Both are frequently CD34 positive

Inflammatory Fibroid Polyp

Solitary Fibrous Tumor

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

Both are usually CD34 positive and may have a perivascular whirling pattern

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

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