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
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.

General

Gross

Features:[2]

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

Microscopic

Features:[2][3]

  • "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.

DDx:

Images

  • Desmoid tumour. (WC)

  • Classic desmoid fibromatosis with delicate curving vessels and sweeping long fascicles.

  • This example of desmoid fibromatosis shows a keloidal collagenous stroma and may evoke keloidal scar or even solitary fibrous tumor.

  • Giant cells are an unusual but occasional component of desmoid fibromatosis. Sometimes the giant cells are histiocytic, sometimes they are entrapped rhabdomyocytes.

  • Intra-abdominal desmoids can overrun vital organs; in this case, the pancreas.

  • Intraabdominal desmoids can extend through the bowel to the mucosa and provoke ulceration.

www:

IHC

Features:[2]

  • 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.

Others:

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

Molecular

  • Point mutations in the CTNNB1 gene (encodes β-catenin).[9]
    • ~85% Sporadic desmoids
    • Constitutive function mutations - β-catenin activity never turns off.
    • β-catenin accumulates in the nucleus.
  • Loss of function mutation in the APC gene.
    • ~15% of sporadic desmoids APC gene.
    • All familial adenomatous polyposis associated desmoids.
    • APC product unavailable to interact with β-catenin.
    • β-catenin is not broken down.
    • Constitutively active β-catenin
    • β-catenin accumulates in the nucleus.

Sign out

LESION, ABDOMINAL WALL, BIOPSY:
- DESMOID-TYPE FIBROMATOSIS.

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

See also

References

  1. ↑ URL: http://www.dtrf.org/dtrf_aboutdesmoids.htm. 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: http://www.surgicalpathologyatlas.com/glfusion/mediagallery/media.php?f=0&sort=0&s=20090717111548196. Accessed on: 4 October 2011.
  4. ↑ 4.0 4.1 4.2 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: http://www.cheapmedicinechest.com/abdominal-pain-and-colonic-obstruction-from-an-intra-abdominal-desmoid-tumor.html. 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.
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