Urinary bladder Pathobasic - WordPress.com · 07.02.2017 · Polypoid cystitis •Up to ¼...
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Urinary bladder
Pathobasic
Pathology Lukas Bubendorf
• Biopsy
• TUR-B
• Resection
• Cytology
– Voided urine, washings
Methods
• Benign lesions
• Neoplastic lesions
Flat
Papillary
Solid
Agenda
Benign lesions
• Nonspecific Cystitis
• Granulomatous (after BCG)
• Eosinophilic cystitis
• Interstitial cystitis
• Polypoid cystitis
• Others…..
Interstitial cystitis
• Unknown etiology
• Middle-aged and older
women
• Nonspecific histology
• Early non-ulcer type
• Classic ulcer type (Hunner)
• Typical histology:
– Hemorrhagic foci
– Mast cells (debatable)
– Ulceration
– Granulation tissue
• Clinical symptoms
• Exclude infection
Polypoid cystitis
• Up to ¼ misdiagnosed
as low-grade UC
• F>M
• Unspecific
• Polypoid, edema,
erythema, non-
branched, broad-based
fronds
• Reactive urothelium
• Low-power!
Von Brunn Nests
• Invaginated nests of of
cytologically benign
urothelial cells
• May be pronounced in
the UUT (ureter)
• Common (-90%)
Differential diagnosis
• Nested UC
• Inverted papilloma
• Paraganglioma
Flat lesions
• Urothelial carcinoma in situ (CIS)
• Reactive urothelial atypia
• Urothelial atypia of unknown
significance
• Urothelial dysplasia
Urinary cytology
High-grade urothelial carcinoma Denuding cystitis
CIS
Schematic representation of CIS
Epstein et al, Biopsy Interpretation, 2016
CIS with early papillary formation
Papillary urothelial neoplasms
• Papilloma
• Inverted papilloma
• PUNLMP
• Papillary UC low-grade
• Papillary UC high-grade
Papillary urothelial proliferation uncertain
malignant potential (UPUMP) (Papillary and flat urothelial hyperplasia)
Urothelial papilloma
• Uncommon
• Younger adults
• Often small
• Recur rarely
<10%
• Normal urothelium
• Vacuolization
Inverted urothelial papilloma
• Benign, rare
• Mostly solitary
• Smooth surface
• Trabecular, glandular
• Palisaded basal cells
• Central spaces with colloid-like m.
Healthy
urothelium pT1
pTa
CIS
pT2-4
-9p/q
p53 mut.
FGFR3 mut
p53 mut. Additional
mutations
Chromosomal
instability
Progression of urothelial carcinoma: genetic model
Hedegaard J et al, Cancer Cell 2016
Molecular pathogenesis of urothelial carcinoma
Hedegaard J et al, Cancer Cell 2016 NMIBC
Cancer Cell 2014;25:152
micropapillary mucinous
plasmacytoid Clear cell
The many faces of divergent differentiation in urothelial carcinoma
Humphrey
Eur Urol
2016
Linder BJ, J Urol 2013
Histological variants – the Mayo experience
(33% of entire cohort)
Nested variant of UC
• Deceptively bland
• Disorderly proliferation crowded small
nests beneath the urotheliom
• Little or no nuclear atypia
• +/- tubules, microcysts
• Myxoid stroma
• Large nested: muscle invasion
• DD: von Brunn nests, inverted low-
grade lesions
Nested variant of UC
Large nested variant of UC
High-grade Low-grade
G1 G2 G3
WHO
2016
WHO
1973
Example: pTa G2 (high-grade)
Training the grading of papillary UC
http://www.isupweb.org