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Bladder

Other carcinomas

Squamous cell carcinoma (general, basaloid, verrucous)


Reviewer: Monika Roychowdhury, M.D., University of Minnesota Medical Center (see Reviewers page)
Revised: 13 June 2011, last major update May 2011
Copyright: (c) 2003-2011, PathologyOutlines.com, Inc.

General
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● 5% of bladder tumors in US, 75% in Egypt/Sudan (in Egypt, bladder cancers are 1/3 of all cancers)
● Mixed urothelial and squamous carcinomas are more common than pure squamous cell carcinomas
● Recommended to diagnose as squamous cell carcinoma only if tumor is solely composed of squamous cell component, with no urothelial carcinoma component (eMedicine)

Sites
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● Most commonly lateral wall and trigone

Clinical features
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● Arises in background of chronic cystitis with squamous metaplasia; also bladder exstrophy, neurogenic bladder, chronic infection, bladder stones, bladder diverticula, chronic indwelling catheters, prolonged cyclophosphamide treatment, Schistosoma haematobium infection in Egypt/Sudan
● Also associated with smoking
● Difficult to detect since arises insidiously; often gross hematuria, dysuria, nocturia, frequency, pain, bacteriuria
● 2/3 of cases occur in females
● De novo cases are usually diagnosed in sixth and seventh decades, but patients with obstructive and irritative symptoms are diagnosed earlier
● 5 year survival is 37% if pT1/pT2 vs. 13% for pT3
● Regional nodal metastasis in 10-25%, distant metastases to bone and lung
● Poorer prognosis if advanced muscle invasive disease at presentation

Gross description
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● Large, ulcerated, necrotic
● Often involves areas other than bladder base
● 80% involve muscular wall at diagnosis
● Surface necrosis and keratin debris are usually present, giving it a flaky, whitish appearance

Gross images
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Squamous cell carcinoma


Cytoprostatectomy specimen

Micro description
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● Arises in epithelium, infiltrates in sheets, nests and islands
● Resembles epidermal tumors with some combination of individual cell keratinization, keratin pearls and intercellular bridges
● TURBT biopsies may contain only keratinous debris
● Keratinization of cells at stromal interface is sign of invasion (per Murphy); cells are polygonal with well defined cell borders, amphophilic to eosinophilic cytoplasm
● Nuclei are pleomorphic, occasionally bizarre, with irregular chromatin and prominent nucleoli
● Mitotic figures are common, as are degenerated cells
● Squamous metaplasia present in 17-60% of nonendemic cases
● Grading is not reproducible

Micro images
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Moderately differentiated tumor

   
Tumor associated with Schistosomiasis

Cytology
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● High index of suspicion needed for detection since many cells resemble squamous metaplasia
● Polygonal, fiber-like or tadpole like cells with well defined cell borders, amphophilic or eosinophilic cytoplasm with occasional vacuoles, enlarged and slightly pleomorphic nuclei with irregular chromatin, prominent nucleoli (if present)
● Poorly differentiated cells resemble any high grade neoplasm

Cytology images
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Keratinizing squamous cell carcinoma

Stains
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● Staining throughout the epithelium for CK5/6 (77%) and CK5/14 (96%)
● Focal staining for CK7 (29%), but negative staining for CK20 and uroplakin III (Virchows Arch 2011;458:301)

Cytogenetics
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● 9p-

Differential diagnosis
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● High grade urothelial carcinoma with squamous component, squamous metaplasia (no anaplasia), condyloma acuminatum with nuclear atypia, verrucous carcinoma, metastatic carcinoma, direct extension of tumors from adjacent organs

Additional references
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Mod Pathol 2004;17:1268 (Schistosomiasis)


Basaloid squamous cell carcinoma

Case reports
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● 60 year woman (Arch Pathol Lab Med 2000;124:455)

Micro description
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● Nests of basaloid cells with numerous mitotic figures
● Areas of squamous differentiation and squamous cell carcinoma in situ

Micro images
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A: nests of basaloid cells with peripheral palisading; B: pseudoglandular pattern


C: invasion of muscularis propria; D: basaloid cells have high N/C ratio and numerous mitotic figures


Adjacent squamous carcinoma in situ


Verrucous squamous cell carcinoma

Definition
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● Almost all cases are associated with Schistosoma hematobium infection
● Indolent growth, spreads by direct extension
● Does not metastasize, although may develop foci of invasive squamous cell carcinoma

Gross description
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● Exophytic, papillary tumor which projects into bladder lumen

Micro
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● Bulbous fronds of well differentiated, acanthotic epithelium with pushing margin, minimal atypia
● No/rare mitotic figures
● May resemble condyloma focally

Micro images
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Exophytic tumor with pushing border in lamina propria

   
Minimal atypia

End of Bladder > Other carcinomas > Squamous cell carcinoma


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