Bladder, ureter & renal pelvis

Urothelial carcinoma - invasive


Last author update: 19 October 2018
Last staff update: 4 April 2023 (update in progress)

Copyright: 2018-2023,, Inc.

PubMed Search: Lipid rich variant urothelial carcinoma

Nicole K. Andeen, M.D.
Page views in 2022: 1,393
Page views in 2023 to date: 1,118
Cite this page: Andeen NK Lipid-rich. website. Accessed September 21st, 2023.
Definition / general
  • An uncommon WHO recognized variant of invasive urothelial carcinoma
  • First described by Mostofi et al in 1999
  • Lipid cell, lipoid cell
  • Presence of cytokeratin and CK7 positive lipoblast-like cells and conventional urothelial carcinoma
  • Consistently negative for mucin (Am J Surg Pathol 2010;34:371)
  • Has areas of conventional UC, distinguishing it from a metastasis
  • May have heterologous liposarcomatous elements but lacks the prominent high grade spindled features of sarcomatoid carcinoma
  • Does not usually coexist with the sarcomatoid variant
Case reports
Gross description
  • Distinct macroscopic features are not well documented
Microscopic (histologic) description
Microscopic (histologic) images

Contributed by Ankur Sangoi, M.D.
  • Similar to conventional high grade invasive urothelial carcinoma
Positive stains
Molecular / cytogenetics description
  • Shows identical loss of heterozygosity (LOH) patterns with the coexistent conventional UC, supporting a shared clonal origin (Am J Surg Pathol 2010;34:371)
Differential diagnosis
Board review style question #1
Which of the following is true about lipid-rich variant of urothelial carcinoma?

  1. It is S100 and vimentin positive
  2. The lipid cell component usually comprises greater than 50% of the urothelial carcinoma
  3. The lipid cells are negative for panCK and CK7, contributing to diagnostic challenges with lipoblasts and liposarcoma
  4. The lipid cells express panCK and CK7 and are negative for mucin, distinguishing this entity from others in the differential diagnosis
Board review style answer #1
D. The lipid cells express panCK and CK7 and are negative for mucin, distinguishing this entity from others in the differential diagnosis. This and the presence of conventional high grade urothelial carcinoma are helpful diagnostic features in the differential diagnoses of lipid-rich variant of urothelial carcinoma with adenocarcinomas with signet ring features, sarcomatoid carcinoma and liposarcoma.

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Reference: Lipid-rich urothelial carcinoma
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