Bladder
Other tumors
Leiomyosarcoma

Author: Gillian Levy, M.D. (see Authors page)

Revised: 8 August 2016, last major update December 2014

Copyright: (c) 2003-2016, PathologyOutlines.com, Inc.

PubMed Search: Bladder leiomyosarcoma
Definition / General
  • Sarcoma of smooth muscle origin, similar to counterparts elsewhere
Epidemiology
  • 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
Sites
  • Occurs at any site in bladder, and can rarely involve the ureter or renal pelvis
Etiology
  • 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
Treatment
  • 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
Micro 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)
Micro Images

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Leiomyosarcoma, urinary bladder

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H&E and smooth muscle actin

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Nuclear pleomorphism is evident

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p53+

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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