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Table of Contents
Definition / general | Essential features | Terminology | Sites | Clinical features | Case reports | Clinical images | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Molecular / cytogenetics description | Differential diagnosis | Additional referencesCite this page: Inflammatory myofibroblastic tumor. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/colontumorimt.html. Accessed July 14th, 2017.
Definition / general
- Low grade mesenchymal neoplasm that can arise in the colonic wall or mesentery, usually of children
- See also topic in Soft tissue chapter
Essential features
- Mesenchymal neoplasm, often pediatric, with spindled cells admixed with inflammation
- t(2;5) (TPM3-ALK) translocation
- Rare aggressive variant called epithelioid inflammatory fibroblastic sarcoma
Terminology
- Older terms include called inflammatory pseudotumor, inflammatory fibrosarcoma and plasma cell granuloma
- "Epithelioid inflammatory fibroblastic sarcoma" refers to a rare, aggressive variant with unique morphologic and molecular features (Am J Surg Pathol 2011;35:135)
Sites
- Can arise in the colonic wall or the mesentery
- Most common site in gastrointestinal tract is stomach
Clinical features
- Patients usually in the pediatric age range (Am J Surg Pathol 2007;31:509)
- Symptoms include anemia, abdominal pain, fever, weight loss and high sedimentation rate (J Pediatr Surg 2001;36:169)
- May recur, but metastases rare; these outcomes may be more common in epithelioid inflammatory fibroblastic sarcoma
Case reports
- 11 year old boy with rectal tumor (Arch Iran Med 2006;9:277)
- 35 year old woman with clinical appendicitis, cecal tumor (Scott Med J 2004;49:157)
Clinical images
Images hosted on other servers:
Endoscopic view of polypoid lesion
Same lesion, on imaging
Gross description
- Circumscribed, often polypoid
Gross images
Images hosted on other servers:
2 cm polypoid lesion with central depression
3.9 cm fungating yellow mass
2 year old boy with colonic mass causing anemia
Microscopic (histologic) description
- Bland spindle cells with abundant amphophilic cytoplasm and variably prominent nucleoli
- Lymphoplasmacytic infiltrate with polyclonal plasma cells
- Background may show myxoid change or laminated / whorled fibrosis
- Epithelioid inflammatory myofibroblastic sarcoma: similar, except cells are more epithelioid, with large nucleoli
Microscopic (histologic) images
Images hosted on Pathout server:
Various images (H&E and IHC)
Spindle cells in
hyaline stroma,
with inflammation
Positive for vimentin
and smooth muscle actin
Not necessarily colon
Contributed by Raul Gonzalez, M.D.
Epithelioid inflammatory myofibroblastic sarcoma
Contributed by Dr. Michael Feely, University of Florida (USA)
Images hosted on other servers:
Inflammatory cells and spindle cells
CD117 negative
Positive stains
- Desmin, smooth muscle actin; variable cytoplasmic ALK1 (Mod Pathol 2002;15:931)
- Epithelioid inflammatory myofibroblastic sarcoma: nuclear membrane ALK1
Molecular / cytogenetics description
- Abnormalities of 2p23, usually t(2;5) (TPM3-ALK) translocation, in approximately half of cases; more common in children (Mod Pathol 2001;14:569)
- Epithelioid inflammatory myofibroblastic sarcoma: t(2;2) RANBP2-ALK translocation
Differential diagnosis
- Inflammatory fibroid polyp: patients older, tumors smaller with more eosinophils and CD34 positivity (Hum Pathol 2002;33:307)
- Fibromatosis: nuclear positivity for beta-catenin
- Schistosomiasis: may rarely form inflammatory pseuotumorous reaction (J Natl Med Assoc 2006;98:1365)
Additional references
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