Desmoid-type fibromatosis

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Desmoid-type fibromatosis
Diagnosis in short

Desmoid-type fibromatosis. H&E stain.

LM "sweeping fascicles"/bundles, spindle cells with small slender nuclei, solid dark eosinophilic cytoplasm, +/-mitoses, long thin-walled vessels - parallel to one another
Subtypes Intra and extra-abdominal types are sometimes considered separately
LM DDx hypertrophic scar, gastrointestinal stromal tumour, retroperitoneal fibrosis, other fibromatoses, nodular fasciitis, schwannoma
IHC beta-catenin +ve (nuclear), SMA +ve/-ve, CD117 -ve
Molecular sporadic point mutations in the CTNNB1 gene which encodes β-catenin
Site soft tissue

Syndromes familial adenomatous polyposis - esp. Gardner syndrome

Prevalence uncommon
Prognosis benign but locally aggressive
Clin. DDx trauma/hematoma

Desmoid-type fibromatosis is a benign soft tissue lesion in the fibroblastic/myofibroblastic group of tumours.

It is also known as desmoid tumour and desmoid fibromatosis.




  • Location:
    • Abdominal wall, proximal extremities - classic for adolescents and women.
    • Head and neck - classic for children.
  • Circumscribed mass.
  • May be quite large (>10 cm).



  • "Sweeping fascicles"/bundles.
  • Spindle cells with:
    • Small slender nuclei.
    • Solid dark eosinophilic cytoplasm.
  • +/-Mitoses - may be abundant.
  • Long thin-walled vessels - parallel to one another - important feature.



  • Intra and extra-abdominal types are sometimes considered separately - somewhat different DDX.





  • Beta-catenin +ve (nuclear[4]) - important.
    • 100% sensitive... may not be completely specific (?).[8]
    • Staining may be difficult to interpret as the nucleus may be small, the cytoplasm scant and the precipitate grainy and vague. Ensure that the staining seen is nuclear (or nuclear and cytoplasmic). Cytoplasmic staining alone can occur and is not a true positive.
  • SMA +ve ~50% of lesions.


  • CD117 -ve.
  • DOG1 -ve.
  • CD34 -ve.



  • Point mutations in the CTNNB1 gene (encodes β-catenin).[9]
    • ~85% of sporadic desmoids [4]
    • β-catenin is abnormally stable.[10]
    • β-catenin accumulates in the nucleus.
  • Loss of function mutation in the APC gene.
    • ~15% of sporadic desmoids.[4]
    • All familial adenomatous polyposis associated desmoids.
    • APC product unavailable to interact with β-catenin.[11]
    • β-catenin is not broken down.
    • β-catenin accumulates in the nucleus.

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The tumour stains strongly with beta-catenin and weakly with SMA. It is negative for CD117.

See also


  1. URL: Accessed on: 15 April 2011.
  2. 2.0 2.1 2.2 Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 609. ISBN 978-0781765275.
  3. URL: Accessed on: 4 October 2011.
  4. 4.0 4.1 4.2 4.3 4.4 Huss, S.; Nehles, J.; Binot, E.; Wardelmann, E.; Mittler, J.; Kleine, MA.; Künstlinger, H.; Hartmann, W. et al. (Jan 2013). "β-catenin (CTNNB1) mutations and clinicopathological features of mesenteric desmoid-type fibromatosis.". Histopathology 62 (2): 294-304. doi:10.1111/j.1365-2559.2012.04355.x. PMID 23020601.
  5. Thalheimer, A.; Meyer, D.; Gattenlöhner, S.; Timmermann, W.; Thiede, A. (Jul 2004). "[Gastrointestinal stromal tumor of the abdominal wall. An unusual localization of a rare tumor].". Chirurg 75 (7): 708-12. doi:10.1007/s00104-003-0696-5. PMID 15257404.
  6. URL: Accessed on: 4 October 2011.
  7. Ma, JH.; Ma, ZH.; Dong, XF.; Yin, H.; Zhao, YF. (Jun 2013). "Abdominal wall desmoid tumors: A case report.". Oncol Lett 5 (6): 1976-1978. doi:10.3892/ol.2013.1297. PMID 23833679.
  8. Amary, MF.; Pauwels, P.; Meulemans, E.; Roemen, GM.; Islam, L.; Idowu, B.; Bousdras, K.; Diss, TC. et al. (Sep 2007). "Detection of beta-catenin mutations in paraffin-embedded sporadic desmoid-type fibromatosis by mutation-specific restriction enzyme digestion (MSRED): an ancillary diagnostic tool.". Am J Surg Pathol 31 (9): 1299-309. doi:10.1097/PAS.0b013e31802f581a. PMID 17721184.
  9. Lazar, AJ.; Tuvin, D.; Hajibashi, S.; Habeeb, S.; Bolshakov, S.; Mayordomo-Aranda, E.; Warneke, CL.; Lopez-Terrada, D. et al. (Nov 2008). "Specific mutations in the beta-catenin gene (CTNNB1) correlate with local recurrence in sporadic desmoid tumors.". Am J Pathol 173 (5): 1518-27. doi:10.2353/ajpath.2008.080475. PMID 18832571.
  10. URL: Accessed on: 4 October 2014.
  11. URL: Accessed on: 4 October 2014.