Ductal Adenocarcinoma

Epidemiology:

• ~3% of prostate CA, mostly combined with acinar adenocarcinoma
• Pure ductal in 0.2-0.4% of prostate cancers

Common sites:

• Periurethral area commonly
• Often extend into the periphery of the prostate

Gross features:

• exophytic growth into urethra sometimes
• often grows along prostatic ducts and usually also invades the prostatic stroma

Histologic features:

• 3% of prostatic carcinomas have both ductal and acinar differentiation
• complex, large glands (GLEASON 4)
• cribriform formations most common
• slit-like lumens often
• comedonecrosis may be present (GLEASON 5)
• endometrioid appearance
• back to back or irregular glands
• myoepithelial cells may be present in cribriform areas
• papillae in exophytic component (useful diagnostic feature, but not found in all) (GLEASON 4)
• note: PIN more likely to have micropapillae
• lined by tall pseudostratified columnar cells
• abundant, amphophylic cytoplasm
• may be pale or eosinophilic or clear
• nuclei elongated maybe
• nuclear atypia more severe than in most acinar adenocarcinomas maybe
• prominent nucleoli common
• coarse chromatin common
• mitotic figures common
• intraluminal necrotic debris commonly (intraductal and invasive components)
• may invade as single glands
• appearance of PIN maybe (PIN-like ductal adenocarcinoma) (GLEASON 3)
• solid areas maybe (poorly differentiated)

Immunophenotype:

Marker:	Sensitivity:	Specificity:
PSAP
PSA	most
AMACR	most
CK20 (neg)	Occasionally may have some patchy staining
ERG	40%

Molecular features:

• TMPRSS2-ERG gene fusion (11%)
• Remarkably similar gene expression between acinar and ductal adenocarcinoma

Other features:

• aggressive course, relatively poor prognosis
• higher stage
• greater risk of biochemical recurrence after radical prostatectomy
• some small tumours may be completely removed by TURP

References:

• Sternberg 2004
• Moch H, Humphrey PA, Ulbright TM, Reuter VE (eds.) WHO Classification of Tumours of the Urinary System and Male Genital Organs (2016)