Other tumors

Author: Nat Pernick, M.D. (see Authors page)

Revised: 9 August 2016, last major update November 2015

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

PubMed Search: Bladder rhabdomyosarcoma
Cite this page: Rhabdomyosarcoma. website. Accessed October 27th, 2016.
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
Micro 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
Micro Images

Images hosted on other servers:
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Uniform spindle cells in myxoid stroma with eosinophilic fibrillary cytoplasm and cigar shaped nuclei

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Figures 1/2: urine cytology shows primitive appearing round cells with minimal cytoplasm, lymphocyte-like nucleus with fine, evenly distributed chromatin and no nucleoli; nesting pattern in some areas (figure 2)

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