Bladder, ureter & renal pelvis
Other tumors

Topic Completed: 1 December 2014

Minor changes: 21 June 2019

Copyright: 2002-2019,, Inc.

PubMed Search: Bladder [title] leiomyoma

Monika Roychowdhury, M.D.
Page views in 2019: 1,057
Page views in 2020 to date: 596
Cite this page: Roychowdhury M. Leiomyoma. website. Accessed August 7th, 2020.
Definition / general
  • Benign smooth muscle tumor, similar to counterparts elsewhere
  • Defined as sharply circumscribed lesions showing little or no mitotic activity and lacking all but minimal cytologic atypia
  • Most common benign soft tissue neoplasm of bladder, but < 0.5% of bladder tumors
  • Mean age 52-61 years, range 22-78 years, no gender preference
Clinical features
  • Usually symptomatic but can be asymptomatic (asymptomatic tumors usually less than 3 cm, Urology 2010;76:1425)
  • Endovesical type most frequently produce obstructive or irritative symptoms
  • Can be definitively diagnosed on biopsy or TUR without the risk of unsampled leiomyosarcoma (Am J Surg Pathol 2010;34:502); cannot necessarily assess circumscription on TUR specimens, but infiltrative pattern should not be present in a leiomyoma
Prognostic factors
  • Lesions with necrosis or mitotic figures, or not well circumscribed, may be well differentiated leiomyosarcoma
  • No risk of progression to leiomyosarcoma even if incompletely resected
Case reports
  • Excision if symptomatic, enlarging mass or unclear diagnosis
Gross description
  • 0.5 - 4.5 cm, well circumscribed
Gross images

Case of the Week #203

Ureter leiomyoma

Microscopic (histologic) description
  • Similar histology to leiomyomas elsewhere (large sheets of intersecting smooth muscle fascicles)
  • Low cellularity
  • May have bizarre or symplastic nuclei, hyalinization, degenerative atypia
  • Occasionally has necrosis or myxoid change
  • Minimal/no mitotic figures, no atypical mitotic figures (Am J Surg Pathol 2002;26:292)
Microscopic (histologic) images

Images hosted on other servers:
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Strong desmin staining

Positive stains
  • Actin and desmin (strong)
Molecular / cytogenetics description
  • Usually diploid
Differential diagnosis
  • Uterine leiomyoma (parasitic): Obstet Gynecol 2009;114:611
  • Well differentiated leiomyosarcoma: not well circumscribed; has necrosis, mitotic figures, abnormal mitotic figures
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