Colon (tumor & nontumor)
Mesenchymal tumors
Fibromatosis
Author: Raul S. Gonzalez, M.D.
Topic Completed: 1 September 2016
Minor changes: 31 July 2020
Copyright: 2002-2019, PathologyOutlines.com, Inc.
PubMed Search: Fibromatosis [title] colon
Table of Contents
Definition / general | Essential features | Terminology | Clinical features | Radiology description | Case reports | Treatment | Clinical images | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Electron microscopy description | Molecular / cytogenetics description | Differential diagnosisCite this page: Gonzalez R. Fibromatosis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/colontumorfibromatosis.html. Accessed August 7th, 2020.
Definition / general
- Colon wall is an uncommon location for aggressive (desmoid) fibromatosis
- See also Soft tissue topic
Essential features
- Locally aggressive mesenchymal proliferation more commonly arising in the mesentery or retroperitoneum
- Associated with Gardner syndrome
Terminology
- Aggressive fibromatosis and desmoid tumor are synonyms
Clinical features
- Mean age 34 years (Am J Surg Pathol 2000;24:947)
- May be associated with trauma, familial adenomatous polyposis, Gardner syndrome, Lynch syndrome (Cancer 1992;69:2049) and hormonal stimulation
Radiology description
- FDG-avid on PET (Br J Radiol 2012;85:e37)
Case reports
- 9 year old boy with intraabdominal tumor invading colonic wall (Eur J Pediatr Surg 2005;15:196)
- 72 year old man with colonic mesenteric tumor causing acute abdomen (Indian J Gastroenterol 2002;21:199)
Treatment
- Surgical excision, radiation therapy, possibly chemotherapy
Clinical images
Images hosted on other servers:
Colonic desmoid on PET / CT
Gross description
- Firm, tan, homogenous
- Usually large (up to 25 cm) with infiltrative borders
Microscopic (histologic) description
- Broad, sweeping fascicles of bland spindle cells with low mitotic activity, bland nuclear features, finely collagenous stroma with evenly spaced blood vessels and infiltrative borders
- Tumor may extend through colonic wall up to muscularis propria
- No necrosis, no hemorrhage, no pleomorphism, no myxoid degeneration, no epithelioid cells, no foam cells
Microscopic (histologic) images
Contributed by Raul S. Gonzalez, M.D.
Various images
Positive stains
- Beta-catenin (nuclear staining), vimentin
- Variable: CD117, smooth muscle actin and desmin
Electron microscopy description
- Myofibroblastic / fibroblastic differentiation
Molecular / cytogenetics description
- Mutations in beta-catenin pathway, including CTNNB1 (Int J Surg Pathol 2016;24:264) and APC, causing nuclear beta-catenin staining
Differential diagnosis
- Gastrointestinal stromal tumor: positive for CD117, negative for beta-catenin
- Inflammatory myofibroblastic tumor: lymphoplasmacytic infiltrate; variably ALK1 positive; negative for beta-catenin
- Sclerosing mesenteritis: areas of fat necrosis and perivascular infiltrates of lymphoid cells; negative for beta-catenin
