Adenocarcinoma of the urinary bladder

Adenocarcinoma of the urinary bladder
Diagnosis in short
Adenocarcinoma of the urinary bladder. H&E stain.
Synonyms	primary adenocarcinoma of the urinary bladder
LM	nuclear pleomorphism (may be mild), usually glandular differentiation (most common), no urothelial differentiation - essential
LM DDx	urachal carcinoma, invasive urothelial carcinoma with glandular differentiation, metastatic adenocarcinoma, direct extension of adenocarcinoma from an adjacent structure (esp. colorectal adenocarcinoma)
IHC	CK7 +ve, CK20 +ve, CDX2 +ve (strong, diffuse), beta-catenin -ve (nuclei -ve, membranes +ve)
Grossing notes	radical cystectomy grossing, cystoprostatectomy grossing
Site	urinary bladder
Signs	+/-hematuria
Prevalence	rare
Treatment	cystectomy

Adenocarcinoma of the urinary bladder, also primary adenocarcinoma of the urinary bladder and bladder adenocarcinoma, is a very uncommon malignant urinary bladder tumour.

General

• Very rare - approximately 0.5-2.0% of bladder cancers.

Clinical:

• Like urothelial carcinoma - usually hematuria.

Microscopic

Features:

• Nuclear pleomorphism - may be mild.
• Usually glandular differentiation (most common).
  • Frequently looks just like colorectal adenocarcinoma.
• Without urothelial differentiation - essential.
• +/-Evidence of invasion such as:
  • Desmoplastic stroma.
  • Extensive disordered or cribriform growth.

Subtypes:

• Glandular.
• Papillary.
• Colloidal (mucinous).
• Signet ring cell carcinoma.
• Clear cell carcinoma (also mesonephroid carcinoma).

Note:

• The presence of adenocarcinoma in situ suggests the lesion arose in the bladder.^{[citation needed]}

DDx:

• Urachal adenocarcinoma - dome of bladder.
• Invasive urothelial carcinoma with glandular differentiation - has urothelial differentiation.
• Metastatic adenocarcinoma or extension of adenocarcinoma from a nearby structure
  • Colorectal adenocarcinoma.
  • Prostatic adenocarcinoma - esp. ductal adenocarcinoma of the prostate.
  • Endometrioid endometrial adenocarcinoma.
• Tubular adenoma of the urinary tract.

Images

Case 1

• 

  Invasive AUB - low mag. (WC)

• 

  Invasive AUB - intermed. mag. (WC)

• 

  Invasive AUB - high mag. (WC)

Case 2 - AIS

• 

  Adenocarcinoma in situ (AIS) - very low mag.

• 

  AIS - low mag.

• 

  AIS - intermed. mag.

• 

  AIS - high mag.

IHC

Features - variable:

• CK7 +ve.
• CK20 +ve.
• CDX2 +ve (strong, diffuse).
• Beta-catenin -ve (negative nuclear staining, positive membranous staining).
  • Colorectal adenocarcinoma typically has nuclear staining and membranous staining.
• Thrombomodulin +ve/-ve (~60% of cases).
  • Colorectal adenocarcinoma -ve.
  • Urothelial carcinoma +ve (~90% of cases).

Images

Case 1

• 

  AUB - beta-catenin - low mag. (WC)

• 

  AUB - beta-catenin - intermed. mag. (WC)

• 

  AUB - beta-catenin - high mag. (WC)

• 

  AUB - beta-catenin - very high mag. (WC)

Sign out

Urinary Bladder Tumour, Transurethral Resection:
- Invasive adenocarcinoma into the lamina propria, see comment.
- Muscularis propria not sampled.
- Negative for lymphovascular invasion.

Comment:
No urothelial carcinoma component is identified. 

The differential diagnosis includes (1) primary adenocarcinoma of the 
bladder, (2) adenocarcinoma from another organ (direct extension or 
metastasis), (3) urothelial carcinoma with glandular differentiation 
without sampled urothelial carcinoma, and (4) urachal adenocarcinoma.

Immunostaining of the tumour is as follows:
POSITIVE: CK7, CK20, CK34betaE12.
NEGATIVE: beta-catenin (membranous pattern only, nuclei are negative).

The immunoprofile (beta-catenin = nuclei negative, CK7 = positive) and 
presence of an in situ component favours a primary adenocarcinoma of 
the bladder; however, this is uncommon. Nonprimary adenocarcinoma 
(e.g. colorectal adenocarcinoma) should be excluded clinically.

See also

• Urinary bladder.
• Adenocarcinoma.