Cytologically bland, at most moderately cellular, deep infiltrative fibroproliferative process primarily involving mesentery or other intra-abdominal sites
Alternate / Historical Names
Intra-abdominal fibromatosis
Musculoaponeurotic fibromatosis
Aggressive fibromatosis
Diagnostic Criteria
Over age 5 years by definition
Essentially the same as abdominal desmoid fibromatosis except for location, positive association with polyposis, lack of association with pregnancy and more diffuse myxoid stroma in some cases
Primarily based in mesentery by definition
If retroperitoneum involved by extension from mesentery, lesion should be considered mesenteric fibromatosis
Peripheral infiltration of bowel wall muscularis may be seen
Low to moderate cellularity
Bland spindle cells in fascicles or haphazard
Nuclei small, dark to slightly enlarged and vesicular
Cytoplasm scant
Stroma may be densely collagenous or myxoid
May have keloid like fibers
Rare metaplastic cartilage and bone
Mitotic figures infrequent
Rarely >5 per HPF
Never atypical
Inflammation not prominent
May be seen focally, usually peripherally
Prominent thin walled dilated veins and thick walled muscular arteries
Gross circumscription may be deceptive
Nearly always over 3 cm
Average 15 cm
Focal hemorrhage may be seen
Hemosiderin rare
May be associated with familial adenomatous polyposis / Gardner syndrome, see Clinical at left
Richard L Kempson MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting/updates: 10/15/07, 12/22/08, 2/8/09, 12/12/09
Supplemental studies
Immunohistology
Actin
50%
Desmin
usually negative, occasionally focal
Beta-catenin
90%
CD117
CD117 frequently negative, variable reports of focal/weak staining
CD34
negative
S100
negative
Keratin
negative
Estrogen receptor
0-10%
Progesterone receptor
0-25%
Response to hormone therapy is not related to receptor status
Reports of frequent strong reaction for CD117 appear to be due to a cross-reacting antibody (Miettinen 2001)
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Fletcher CDM, Unni KK, Mertens F. Pathology and Genetics of Tumours of Soft Tissue and Bone, World Health Organization Classification of Tumours 2002
Weiss SW, Goldblum JR. Enzinger and Weiss's Soft Tissue Tumors, 4th edition, 2001
Hoos A, Lewis JJ, Antonescu CR, Dudas ME, Leon L, Woodruff JM, Brennan MF, Cordon-Cardo C. Characterization of molecular abnormalities in human fibroblastic neoplasms: a model for genotype phenotype association in soft tissue tumors. Cancer Res 2001 Apr 1;61(7):3171-5
De Wever I, Dal Cin P, Fletcher CD, Mandahl N, Mertens F, Mitelman F, Rosai J, Rydholm A, Sciot R, Tallini G, Van Den Berghe H, Vanni R, Willen H. Cytogenetic, clinical, and morphologic correlations in 78 cases of fibromatosis: a report from the CHAMP Study Group. CHromosomes And Morphology. Mod Pathol 2000 Oct;13(10):1080-5
Burke AP, Sobin LH, Shekitka KM, Federspiel BH, Helwig EB. Intra-abdominal fibromatosis. A pathologic analysis of 130 tumors with comparison of clinical subgroups. Am J Surg Pathol. 1990 Apr;14(4):335-41.
Rodriguez JA, Guarda LA, Rosai J. Mesenteric fibromatosis with involvement of the gastrointestinal tract. A GIST simulator: a study of 25 cases. Am J Clin Pathol. 2004 Jan;121(1):93-8.
Montgomery E, Torbenson MS, Kaushal M, Fisher C, Abraham SC. Beta-catenin immunohistochemistry separates mesenteric fibromatosis from gastrointestinal stromal tumor and sclerosing mesenteritis. Am J Surg Pathol. 2002 Oct;26(10):1296-301.
Yantiss RK, Spiro IJ, Compton CC, Rosenberg AE. Gastrointestinal stromal tumor versus intra-abdominal fibromatosis of the bowel wall: a clinically important differential diagnosis. Am J Surg Pathol. 2000 Jul;24(7):947-57.
Miettinen M. Are desmoid tumors kit positive? Am J Surg Pathol. 2001 Apr;25(4):549-50.