Bladder
Urothelial carcinoma-invasive
Undifferentiated carcinoma



Topic Completed: 1 December 2014

Revised: 24 December 2018

Copyright: (c) 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: Undifferentiated carcinoma[title]
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Cite this page: Parakh R Undifferentiated carcinoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/bladderundifferentiated.html. Accessed June 16th, 2019.
Definition / general
  • Rare poorly differentiated pleomorphic carcinoma that cannot be otherwise classified
  • ICD-O: 8020/3
Clinical features
  • Very rare if exclude other undifferentiated carcinomas with distinct histologic features indicated above
  • Advanced stage at presentation with nodal metastases
  • Poorer survival than urothelial carcinoma NOS of similar stage (Pathology 2010;42:364)
Microscopic (histologic) description
  • Sheets of usually large polygonal or round cells with moderate to abundant cytoplasm, distinct cell borders
  • Usually 90%+ of tumor is composed of large cell component
  • Tumor is either infiltrative or has solid expansile nests with variable dyscohesive growth
  • By definition, no features of other histologic types are present
Positive stains
Differential diagnosis
  • Lymphoma: morphology of lymphoma subtype, negative for keratin, positive for lymphocytic markers
  • Melanoma: spindled or epithelioid; prominent nucleoli; positive for melanocytic markers
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