Bladder, ureter & renal pelvis

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Last staff update: 15 November 2021

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PubMed Search: Bladder rhabdomyosarcoma

Nat Pernick, M.D.
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Cite this page: Pernick N. Rhabdomyosarcoma. website. Accessed September 25th, 2023.
Definition / general
  • Sarcoma with features of skeletal muscle differentiation
  • Either embryonal (botryoid or spindle cell), alveolar or pleomorphic rhabdomyosarcoma
  • Less than 0.5% of all bladder tumors, but one of most common tumors of the lower urogenital tract in children
  • Often children 2-6 years old; 75% male
  • Adult tumors are usually alveolar or unclassified, commonly with anaplasia, and resemble small cell carcinoma (Am J Surg Pathol 2008;32:1022)

    Botryoid variant:
  • Occurs in mucosal lined, hollow cavities (vagina, nasal cavity, bladder); most common bladder tumor in children
  • May be associated with Wilms tumor and Dandy-Walker syndrome
  • Usually in trigone
  • Infiltrates adjacent tissue but distant metastases are rare
  • Arise from primitive muscle cells
Clinical features
Prognostic factors
  • Favorable prognostic factors: children vs. adults, embryonal histology, low stage, polypoid (exophytic) growth pattern [10 year survival is 92% vs. 68% for diffuse intramural (endophytic) growth pattern]
Case reports
Gross description
  • Mucoid, polypoid
  • Botryoid tumors resemble a bunch of grapes
Microscopic (histologic) description
  • Myxomatous stroma with scattered, small, blue malignant cells, usually compressed beneath intact urothelium (cambium layer)
  • Cross striations are often difficult to identify in untreated cases
Positive stains
Negative stains
Molecular / cytogenetics description
  • Alveolar subtype has translocations between #13 FKHR gene and either #2 - PAX3 or #1 - PAX7 gene
  • Embryonal subtype has 11p-
Differential diagnosis
  • Carcinomas (urothelial or small cell) with rhabdomyosarcomatous differentiation:
    • Have distinct epithelial component
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