Uterine tumours

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This article deals with uterine tumours, with the exception of the tumours that arise from the endometrium.

Uterine tumours are like water in the sea - very very common. Many hysterectomies are done for them. The most common are leiomyomata (AKA fibroids).

Pre-malignant endometrium and endometrial tumours are dealt with in the articles, endometrial hyperplasia and endometrial carcinoma.

Common benign

Uterine leiomyoma

  • Often called fibroids.

Uncommon benign

Uterine adenofibroma


  • Uncommmon.
  • Benign looking lesions can reoccur.[1]
    • It has been proposed that these lesions are in fact well-differentiated adenosarcomas.[2]



  • Moderately demarcated lesion with:
    • Pale stroma and epithelioid/spindle cells.
    • Simple cuboidal (or columnar) epithelium with eosinophilic cytoplasm.
  • Low mitotic rate.
  • Nuclear atypia minimal.



  • Adenosarcoma.


Adenomatoid tumour

Should not be confused with the bone tumour adamantinoma.

Uncertain malignant potential

Smooth muscle tumour of uncertain malignant potential

  • Abbreviated STUMP.


Uterine carcinosarcoma

  • AKA malignant mixed muellerian tumour, abbreviated MMMT.

Adenosarcoma of the uterus

  • AKA uterine adenosarcoma.

Uterine leiomyosarcoma


  • Poor prognosis.
  • Do not (generally) arise from leiomyomas.
  • Often singular, i.e. one tumour; unlike leiomyomas (which are often multiple).



  • "Fleshy" appearance.
  • Necrosis.
  • Large size.
  • Often singular, i.e. one lesion; leiomyomata are often multiple.



  • Smooth muscle differentiation - essential.
    • Fascicular architecture.
      • Whorled look at low power.
      • Groups of spindle cells cut peripendicular to their long axis adjacent to groups of spindle cells cut in the plane of their long axis.
    • May rely on IHC - if poorly differentiated.
  • Malignant histomorphologic features - two of three required - key features:[3]
    1. Nuclear pleomorphism.
    2. Coagulative tumour cell necrosis
      • Should be patchy/multifocal.
      • Zonal necrosis is suggestive of vascular cause and may be a degenerative change.
        • Zonal necrosis may be seen in (benign) leiomyomas.
    3. Mitoses.
      • 10 mitoses/10 HPF.
      • 5 mitoses/10 HPF - if epithelioid.
      • 2 mitoses/10 HPF - if myxoid.


  • The mitotic rate seems to be a relatively weak predictor; a modest rate may be malignant and a high rate benign.[4]



  • CD10 -ve.
  • Positive for SMC markers.
    • Desmin - present in all three types of muscle.
    • Caldesmon.
    • Smooth muscle myosin.
  • p16 +ve.[5]
    • Useful for differentiation from leiomyoma.

Endometrial stromal tumours

This grouping includes the gamut from benign to malignant.


WHO classification:[6]

  • Endometrial stromal nodule - not a tumour.
  • Endometrial stromal sarcoma (ESS), low grade.
  • Undifferentiated endometrial sarcoma (UES).


  • Some believe in a "high grade ESS"... some don't.[7]

Endometrial stromal nodule

  • Abbreviated ESN.


  • Benign.



  • Well-circumscribed - key feature.
    • The interface of the lesion may not have more than three finger-like irregularities/projections into the surround myometrium that are >= 3 mm.[8]
      • If it does... it is an ESS.
  • No vascular invasion.



Endometrial stromal sarcoma

  • Abbreviated ESS.
  • Previously known as low-grade endometrial stromal sarcoma.

Undifferentiated endometrial sarcoma

  • Abbreviated as UES.
  • Previously known as high-grade endometrial stromal sarcoma.[9]




  1. Marked nuclear atypia.
  2. Mitoses+++.
  3. Poorly differentiated - key feature
    • Looks nothing like low grade endometrial stromal sarcoma.
    • Negative for smooth muscle markers (to exclude leiomyosarcoma).


  • Need IHC to diagnose.




  • SMA ~50% +ve.

Typically negative:[10]

  • Smooth muscle markers: desmin, h-caldesmon.
  • Skeletal muscle markers: Myf4, actin.
  • Melanoma: S100, HMB-45.
  • GIST: CD117.

Weird stuff

Trophoblastic tumours

Uterine tumour resembling an ovarian sex cord stromal tumour

  • Abbreviated UTROSCT.

Atypical polypoid adenomyoma of the uterus

  • Abbreviated APA.
  • AKA atypical polypoid adenomyoma.

See also


  1. Seltzer, VL.; Levine, A.; Spiegel, G.; Rosenfeld, D.; Coffey, EL. (Jun 1990). "Adenofibroma of the uterus: multiple recurrences following wide local excision.". Gynecol Oncol 37 (3): 427-31. PMID 2351327.
  2. Gallardo, A.; Prat, J. (Feb 2009). "Mullerian adenosarcoma: a clinicopathologic and immunohistochemical study of 55 cases challenging the existence of adenofibroma.". Am J Surg Pathol 33 (2): 278-88. doi:10.1097/PAS.0b013e318181a80d. PMID 18941402.
  3. Ip, PP.; Cheung, AN. (Dec 2011). "Pathology of uterine leiomyosarcomas and smooth muscle tumours of uncertain malignant potential.". Best Pract Res Clin Obstet Gynaecol 25 (6): 691-704. doi:10.1016/j.bpobgyn.2011.07.003. PMID 21865091.
  4. Guo, L.; Liu, T.; Huang, H. (Oct 1996). "[Reappraisal of the pathological criteria for uterine leiomyosarcoma].". Zhonghua Bing Li Xue Za Zhi 25 (5): 266-9. PMID 9388868.
  5. Gannon, BR.; Manduch, M.; Childs, TJ. (Jan 2008). "Differential Immunoreactivity of p16 in leiomyosarcomas and leiomyoma variants.". Int J Gynecol Pathol 27 (1): 68-73. doi:10.1097/pgp.0b013e3180ca954f. PMID 18156978.
  6. Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 426. ISBN 978-0781765275.
  7. Amant F, Vergote I, Moerman P (November 2004). "The classification of a uterine sarcoma as 'high-grade endometrial stromal sarcoma' should be abandoned". Gynecol. Oncol. 95 (2): 412–3; author reply 413. doi:10.1016/j.ygyno.2004.07.021. PMID 15491769. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WG6-4DF46J8-3&_user=1166899&_coverDate=11%2F01%2F2004&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1204975755&_rerunOrigin=google&_acct=C000051839&_version=1&_urlVersion=0&_userid=1166899&md5=d6ec1eee2941460a085d1dac6615b5a5.
  8. Baker, P.; Oliva, E. (Mar 2007). "Endometrial stromal tumours of the uterus: a practical approach using conventional morphology and ancillary techniques.". J Clin Pathol 60 (3): 235-43. doi:10.1136/jcp.2005.031203. PMID 17347285. http://jcp.bmj.com/content/60/3/235.full.
  9. Feng, W.; Malpica, A.; Skaland, I.; Gudlaugsson, E.; Robboy, SJ.; Dalen, I.; Hua, K.; Zhou, X. et al. (2013). "Can proliferation biomarkers reliably predict recurrence in world health organization 2003 defined endometrial stromal sarcoma, low grade?". PLoS One 8 (10): e75899. doi:10.1371/journal.pone.0075899. PMID 24146786.
  10. 10.0 10.1 Abeler, VM.; Nenodovic, M. (May 2011). "Diagnostic immunohistochemistry in uterine sarcomas: a study of 397 cases.". Int J Gynecol Pathol 30 (3): 236-43. doi:10.1097/PGP.0b013e318200caff. PMID 21464730.