Bladder, ureter & renal pelvis
Other tumors

Topic Completed: 1 December 2014

Minor changes: 27 June 2019

Copyright: 2003-2019,, Inc.

PubMed Search: Bladder leiomyosarcoma

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Cite this page: Levy G. Leiomyosarcoma. website. Accessed August 7th, 2020.
Definition / general
  • Sarcoma of smooth muscle origin, similar to counterparts elsewhere
  • Usually men
  • Mean age 49-64 years
  • Increased risk after cyclophosphamide treatment (Mod Pathol 2003;16:512) or radiotherapy; possibly after hereditary retinoblastoma (J Clin Pathol 2003;56:233)
  • Acrolein, a metabolite of cyclophosphamide, is excreted in urine and may cause hemorrhagic cystitis, increasing risk for various bladder cancers
  • Occurs at any site in bladder, and can rarely involve the ureter or renal pelvis
  • Rare (0.1% of bladder malignancies), but most common nonepithelial malignancy of bladder
  • Arises from urinary bladder smooth muscle
Clinical features
  • Aggressive; > 60% develop metastases or die of disease
  • Even low grade tumors may metastasize (Am J Surg Pathol 2002;26:292)
  • 5 year survival rate for high grade leiomyosarcoma is 62%
Prognostic factors
  • Generally poor prognosis with local recurrence or metastatic disease
Case reports
  • Radical cystectomy with wide margins (Int Urol Nephrol 2008;40:311)
  • Systemic chemotherapy for metastases or combined with radiation therapy prior to surgery for improved resectability
Gross description
  • Mean 7 cm, range 3-15 cm, often in bladder dome, well or poorly circumscribed, invasive with ulcerating surfaces
  • Necrosis is frequently found in high grade lesions
Microscopic (histologic) description
  • Cellular, interlacing fascicles of spindled cells with eosinophilic cytoplasm, paranuclear cytoplasmic vacuoles and blunt ended nuclei
  • Usually has infiltrative margins and invades muscularis propria (Am J Surg Pathol 1989;13:480)
  • Variable nuclear atypia
  • Coagulative tumor necrosis common
  • May be myxoid and resemble inflammatory pseudotumor
  • High grade: moderate / marked cytologic atypia, 5+r mitotic figures / 10 HPF or abundant necrosis
  • Myxoid subtype: may resemble inflammatory myofibroblastic tumor, but has destruction of muscle fascicles at tumor-muscle interface; also nuclear pleomorphism and tumor necrosis (not present in inflammatory myofibroblastic tumor)
Microscopic (histologic) images

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Leiomyosarcoma, urinary bladder

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H&E and smooth muscle actin

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Epithelioid subtype

Cytology description
  • Spindle cells with mild to moderate nuclear hyperchromasia
Positive stains
Molecular / cytogenetics description
  • Usually not diploid
Differential diagnosis
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