Bladder, ureter & renal pelvis

Urothelial carcinoma - invasive

With squamous differentiation



Topic Completed: 1 December 2014

Minor changes: 22 November 2021

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PubMed Search: Urothelial carcinoma invasion with squamous differentiation

Nat Pernick, M.D.
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Cite this page: Pernick N. With squamous differentiation. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/bladdersquamousdiff.html. Accessed December 8th, 2021.
Definition / general
  • Mixed variant with malignant urothelial and squamous components (either component may be in situ only)
Epidemiology
Clinical features
Microscopic (histologic) description
  • Associated with high grade urothelial carcinoma
  • By definition, must also have an identifiable malignant urothelial component (may be only carcinoma in situ)
  • Squamous component has nests of malignant squamous epithelium, characterized by polygonal cells and evidence of keratinization (dyskeratosis, keratin pearls) or intercellular bridges
  • Squamous component may have basaloid or clear cell features
  • Associated with eosinophils (J Clin Pathol 1984;37:500)
  • Recommended to report percentage of squamous component
Microscopic (histologic) images

AFIP images

High grade tumor



Images hosted on other servers:
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Keratin pearl formation

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Fig 1: Trigone mucosa

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Poorly differentiated
tumor with squamous
differentiation

Positive stains
Negative stains
  • Squamous component: uroplakins (positive in urothelial component), CK20
Differential diagnosis
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