Intraductal carcinomas of the prostate (IDCP) are a new subtype of prostate cancer that has been included as a new entity in the WHO classification of prostate tumors in 2016.
On this page:
Epidemiology
Intraductal carcinomas of the prostate are rarely found isolated on needle core biopsy samples in 0.1-0.3% of the cases 1,2 and are uncommonly (up to 3%) found in the presence of another invasive prostate adenocarcinoma 1.
Associations
Intraductal carcinomas of the prostate are often associated with the following conditions 1,3:
- invasive acinar or ductal adenocarcinoma
- average Gleason score of 8
- extraprostatic extension or seminal vesicle invasion
Diagnosis
The diagnosis of intraductal carcinomas of the prostate is based on typical histological features.
Clinical presentation
If associated with invasive prostate adenocarcinoma, intraductal carcinomas might present with an elevated or rise in prostate-specific antigen (PSA). They also might present with voiding symptoms or hematuria.
Pathology
Intraductal carcinomas of the prostate are classified as carcinoma in situ with similarities to high-grade prostatic intraepithelial neoplasia (HGPIN) but with more cytological atypia and/or expansion of the glandular architecture atypia and frequently associated with high-grade and high-stage prostate cancer 1-4.
Intraductal carcinoma should not be assigned a Gleason grade as per se though 1,3, but require repeat biopsy and/or imaging 1,4.
Location
As the name suggests, intraductal carcinomas of the prostate are located within the periurethral ducts 1.
Microscopic appearance
Microscopically intraductal carcinomas of the prostate include the following histological features 1,3,4:
- expansile growth of atypical cells
- solid, dense or loose cribriform growth pattern
- micropapillary pattern
- marked nuclear atypia
- comedo necrosis
Immunophenotype
Immunohistochemistry stains are usually positive for ERG and negative for PTEN, which might aid in the differentiation to high-grade prostatic intraepithelial neoplasia (HGPIN) 1,4.
Genetics
Rearrangements or fusions in the ERG gene are commonly observed in prostatic intraductal carcinomas 2-4.
Radiographic features
Imaging in the case of intraductal carcinomas of the prostate is done to detect associated invasive prostate cancer.
MRI
Intraductal carcinoma of the prostate on core needle biopsy sample should prompt further evaluation with multiparametric MRI, in which the potentially associated clinically significant invasive prostate adenocarcinoma should be meticulously searched for. Evaluation and reporting are most commonly performed with the PI-RADS system. A subsequent MRI targeted biopsy in case suspicious focal findings should be initiated together with a repeat systematic biopsy.
Radiology report
The radiological report should include a likelihood score, e.g. PI-RADS. If suspicious lesions are found, they should include a description of the following:
- form, location and size
- tumor margins
- extraprostatic extension
- seminal vesicle invasion
- bladder or rectal invasion
- suspicious or enlarged lymph nodes
Treatment and prognosis
Management of intraductal carcinoma of the prostate includes a further search for potentially associated invasive adenocarcinoma with both targeted and systematic biopsy 4-6; otherwise, management is controversial with some favoring radical prostatectomy which should be considered in case of association with low-grade invasive prostate carcinoma.
History and etymology
The first report describing an intraductal carcinoma in an autopsy was by EP Gaynor in 1938 3. It was described as a separate entity by J Kovi and colleagues in 1985 3, and its association to acinar carcinoma was first reported by JE McNeal and CE Yemoto in 1996 6.
Differential diagnosis
The differential diagnosis of intraductal carcinoma of the prostate includes the following conditions 2-4:
Unable to process the form. Check for errors and try again.