Prostate cancer (MR in-bore biopsy)

Case contributed by Dr Joachim Feger

Presentation

Prostate-specific antigen (PSA) 4.7 ng/mL has risen from 3.8 ng/mL, measured one year ago. Previous negative TRUS prostate biopsy.

Patient Data

Age: 65 years
Gender: Male
MRI

mpMRI of the prostate

Findings:

Quality: no major artefacts

Size: 45 x 40 x 45 mm (CC x AP x ML) ≈ 42 mL, PSA density ≈ 0.11 ng/mL2.

Hemorrhage: none

Peripheral zone (PZ): slightly heterogeneous high signal

Focal lesion #1:

Location: left midgland, peripheral zone, posterolateral (LM-PZpl), visible on axial  images (im 15), sagittal images (im 9)

Size: 11 x 6 mm

T2W: circumscribed homogeneous, hypointense with broad capsular contact (~10mm) and a small area of capsular retraction - category 4/5

DWI: focal markedly hyperintense on DWI (b1000) and markedly hypointense on ADC - category 4/5

DCE: focal early enhancement - positive

Transition zone (TZ): moderate heterogeneity representing small volume BPH.

Prostate margin: probable extraprostatic extension left peripheral margin (broad capsular contact ~10mm, small area of capsular retraction)

Lesion overall PI-RADS category: 4/5

Neurovascular bundles: probably involved, directly adjacent to lesion #1

Seminal vesicles: contracted, not involved

Lymph nodes: multiple oval iliac lymph nodes (up to 7 mm size, fatty hilum, smooth margins)

Pelvic bones: no osseous metastases suggested

Other pelvic organs: normal
 

Impression:

Highly suspicious lesion in the left peripheral zone (PZpl) - (PI-RADS 4).

There is probable extraprostatic extension on the left, which would make it PI-RADS 5 – MRI putative stage: cT3a.

MRI-targeted prostate biopsy was recommended.

See also: Prostate Imaging - Reporting and Data System (PI-RADS)

MRI

MR in-bore biopsy

MRI in-bore biopsy (done in ambulatory setting):

Patient preparation:

Coagulation parameters (INR, aPTT) were performed and reviewed before the procedure.

Written informed consent was obtained.

Periprocedural antibiotics were administered.

Fasting for 4 hours before the procedure. Rectal cleansing with enema.

Procedural details:

The patient is placed in a prone position on the MRI table.

After a digital rectal exam (DRE) and intrarectal instillation of sterile lidocaine gel, the needle guide is introduced into the patient's rectum.

A portable biopsy device is connected to the MRI table and to the needle guide.

Sagittal and oblique T2W image stacks, as well as axial T2W and DWI sequences, are acquired.

Image sequences are transferred to a planning workstation.

The needle guide is used as a fiducial reference point and calibrated to the system with the software.

The suspicious lesion in the left midglandular, posterolateral zone (LM-PZpl) is re-identified on the images, marked and locked using the software.

Planning coordinates and needle length are obtained.

This information is used to direct the needle guide of the biopsy device in the MRI gantry.

Control oblique T2W images are obtained to verify the accurate orientation of the needle guide in relation to the suspicious lesion.

An 18G, 150 mm biopsy needle is introduced.

Oblique T2W images are obtained again to document the biopsy needle position within the lesion.

Two biopsy cores are obtained from the lesion, registered and sent to pathology.

Needle guide was withdrawn and a tampon soaked with antiseptic gel is introduced into the rectum.

Postprocedural care:

The patient was instructed to remove the placed tampon after ~4 hours and to wait in the waiting room until his first void and then to report back to the radiologist afterwards. This is to ensure timely pick up of complications, e.g. urinary retention or intense post-biopsy bleeding.

In this case, the patient urinated with no significant complications and only small traces of blood in the urine, but no clots, and was sent home.

Case Discussion

This case demonstrates the interpretation and reporting of a multiparametric MRI (mpMRI) of the prostate following the Prostate Imaging - Reporting and Data System (PI-RADS v2.1) 1,2.

The lesion in the posterolateral peripheral zone of the left midgland was assessed as PI-RADS 4, because of its size (<15 mm) and no “definite” signs of extraprostatic extension, although the latter might be suggested because of the broad capsular contact and a small area of retraction. Nevertheless, the lesion is likely clinically significant and thus MRI-targeted prostate biopsy was recommended.

The procedure of the conducted MR in-bore biopsy is illustrated in this case.

Histology of the biopsy revealed a continuous infiltrate of an acinar adenocarcinoma (modified Gleason Score 4+3=7b, G2b, high grade) within both cores.

The patient underwent robot-assisted, laparoscopic, unilateral intrafascial, nerve-conserving, prostatovesiculectomy with pelvic lymphadenectomy and subsequent hormone therapy.

Final histology of the prostatovesiculectomy preparation revealed poorly differentiated acinar adenocarcinoma in both lobes accentuated on the left side with ~10% of prostate volume and with capsular penetration (1 mm depth) and infiltration of lymph vessels and perineural tissue. 

Grading G3, Gleason Score 4+4=8, WHO grade 4.

PlayAdd to Share

Case information

rID: 72546
Published: 30th Nov 2019
Last edited: 26th Feb 2020
Inclusion in quiz mode: Included