Bladder
Urothelial carcinoma-invasive
Lipid cell variant


Topic Completed: 19 October 2018

Revised: 24 December 2018

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

PubMed Search: Lipid cell variant urothelial carcinoma

Nicole K. Andeen, M.D.
Page views in 2018: 82
Page views in 2019 to date: 432
Cite this page: Andeen NK Urothelial carcinoma, lipid cell variant . PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/bladderlipidcell.html. Accessed October 22nd, 2019.
Definition / general
  • An uncommon WHO recognized variant of invasive urothelial carcinoma
  • First described by Mostofi et al in 1999
Terminology
  • Lipid cell, lipid rich, lipoid cell
Epidemiology
Etiology
Diagnosis
  • 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 Dr. Ankur Sangoi

Treatment
  • 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 question #1
Which of the following is true about lipid cell variant of urothelial carcinoma?

A. It is S100 and vimentin positive
B. The lipid cell component usually comprises greater than 50% of the urothelial carcinoma
C. The lipid cells are negative for panCK and CK7, contributing to diagnostic challenges with lipoblasts and liposarcoma
D. The lipid cells express panCK and CK7 and are negative for mucin, distinguishing this entity from others in the differential diagnosis
Board review 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 cell variant of urothelial carcinoma with adenocarcinomas with signet ring features, sarcomatoid carcinoma and liposarcoma.
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