Urothelial carcinoma-invasive
Undifferentiated carcinoma

Author: Rugvedita Parakh, M.D. (see Authors page)

Revised: 27 July 2016, last major update December 2014

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

PubMed Search: Undifferentiated carcinoma[title]
Cite this page: Undifferentiated carcinoma. website. Accessed October 20th, 2018.
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