Bladder & urothelial tract
Urothelial carcinoma - invasive
With squamous differentiation
Author: Nat Pernick, M.D.
Last author update: 1 December 2014
Last staff update: 7 February 2024 (update in progress)
Copyright: 2003-2024, PathologyOutlines.com, Inc.
PubMed Search: Urothelial carcinoma invasion with squamous differentiation
Table of Contents
Definition / general | Epidemiology | Clinical features | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Differential diagnosisCite this page: Pernick N. With squamous differentiation. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/bladdersquamousdiff.html. Accessed April 19th, 2024.
Definition / general
- Mixed variant with malignant urothelial and squamous components (either component may be in situ only)
Epidemiology
- Occurs in 21% of urothelial carcinomas of bladder (Arch Pathol Lab Med 2007;131:1244)
Clinical features
- Clinical significance uncertain, but appears to be unfavorable prognostic factor (Int Braz J Urol 2007;33:339, Urology 2007;70:69)
- May be resistant to radiotherapy (J Clin Pathol 1989;42:250)
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
Contributed by @katcollmd on Twitter and AFIP
Urothelial carcinoma with squamous differentiation
High grade tumor
Images hosted on other servers:
Keratin pearl formation
Fig 1: Trigone mucosa
Poorly differentiated
tumor with squamous
differentiation
Positive stains
- Squamous component: CK14, Mac387 (L1 antigen) (J Clin Pathol 2007;60:332)
- Also CK5/6, CK5/14 (Virchows Arch 2011;458:301)
- Caveolin-1 (Am J Clin Pathol 2003;120:93)
Negative stains
- Squamous component: uroplakins (positive in urothelial component), CK20
Differential diagnosis
- Squamous cell carcinoma:
- No associated urothelial component (i.e. pure squamous cell component)
