Prostate cancer - staging

Case contributed by Dr Joachim Feger

Presentation

Histologically proven prostate cancer. Prostate-specific antigen (PSA) 12.1 ng/mL. Radiation therapy planning.

Patient Data

Age: 80 years
Gender: Male
MRI

Biparametric MRI of the prostate (bpMRI)

Findings:

Quality:  some patient movement between sequences, does not impair diagnostic confidence

Prostate size:    43 x 35 x 47 mm (CC x AP x ML) ≈ 37 mL, PSA density ≈ 0.33 ng/mL2

Hemorrhage:  small bleeding in the left posterior transition zone

Peripheral zone (PZ):  focal findings as below, beyond that mild hypointensities

Focal lesion #1:

  • circumscribed T2 homogenous moderate hypointense focus (18 x 10 x 15 mm) of the left midglandular, anterior and apical, peripheral zone (LM-Pza) with diffusion restriction and indistinct margin of the pseudocapsule
  • visible on axial images (ima 8 -12), sagittal images (ima 4-6)

Focal lesion #2:

  • circumscribed T2 homogenous moderate hypointense focus (25 x 10 x 15 mm) of the left posterolateral base with a capsular breach, and diffusion restriction
  • adjacent asymmetric moderate hypointense signal intensity in the left central zone (CZ) surrounding the left ejaculatory duct and extending into the left seminal vesicle
  • visible on axial images (ima 14-16), sagittal images (ima 4-9), coronal images (ima 24-27)

Focal lesion #3:

  • thin, circumscribed T2 homogenous moderate hypointense focus (8 x 2 x 8 mm) of the midglandular peripheral zone (RM-PZpl) adjacent to the capsule
  • visible on axial images (ima 9), coronal images (ima 25)

Transition zone (TZ):  moderate heterogeneity, multiple BPH nodules, indistinct pseudocapsule left mid gland anterior and left posterior transition zone (LM-TZ)

Prostate margin:  lesion #2 with capsular contact and breach (axial ima 15/16)

Neurovascular bundles:  probably involved

Seminal vesicles:  left seminal vesicle hypointense with diffusion restriction suggestive of seminal vesicle invasion

Lymph nodes:  round lymph node (6mm size, fatty hilum) in the left perirectal fat tissue (T2w ima 1), oval external iliac lymph nodes (up to 5 mm size, fatty hilum, smooth margins)

Pelvic bones:  no signs of bony metastasis

 

Impression:

Multifocal prostate cancer with lesions in the left anterior peripheral zone and with involvement of the pseudocapsule and in the posterior mid gland and base with probable infiltration of the left central zone.

There is a possible small lesion of the right midglandular, posterolateral peripheral zone.

There are signs of extraprostatic extension at the posterolateral base and signs of left seminal vesicle invasion.

MRI putative stage: cT3bNxMx

Annotated image

Key images:

Focal lesion #1:

T2 moderately hypointense focus with diffusion restriction in the left mid gland (red arrow). There is an indistinct margin of the pseudocapsule (blue arrowhead).

Focal lesion #2:

T2 moderately hypointense focus with diffusion restriction and capsular breach (blue arrow) in the left base of the prostate. Asymmetric T2 moderately hypointense signal intensity in the left central zone (CZ) involving the left ejaculatory duct and extending into the left seminal vesicle (green arrowhead).

Focal lesion #3:

Thin in T2 hypointense lesion with diffusion restriction adjacent the capsule of the right peripheral posteromedial zone (orange arrow).

Seminal vesicles:

The left seminal vesicle is asymmetrically thickened and hypointense in T2 with focal low signal in ADC suggestive of left seminal vesicle invasion (green arrows).

Findings illustrated on a map.

Biopsy results:

Histology of the US-guided systematic biopsy 4 months prior to the MRI showed an acinar adenocarcinoma (modified Gleason score 4+4=8, high grade within one core and 3+4=7a low grade within two cores)  of the left mid gland and base and a low-grade acinar adenocarcinoma (modified Gleason score 3+3=6) within one core taken from the right lateral base. The 8 remaining biopsy cores were negative.

The results of the systematic biopsy illustrated.

Case Discussion

This case shows an already histologically proven multifocal prostate cancer.

Histology of the systematic biopsy taken 4 months earlier showed intermediate and high-grade acinar adenocarcinoma (modified Gleason score 3+4=7a and 4+4=8)  of the left base and mid gland and low-grade acinar adenocarcinoma (modified Gleason score 3+3=6) within one core taken from the right lateral base.

MRI, which was done for radiation therapy planning and staging purposes, reflects the findings in the left lobe and also shows a possible small lesion of the right apical/midglandular posterolateral peripheral zone. The right lateral base appears normal on MRI, which could be due to either the low Gleason score or the positive biopsy sample being taken from a more apical location than labeled.

The lesion in the left posterolateral base of the prostate shows signs of extraprostatic extension (capsular contact and capsular breach).

The MRI also suggests involvement of the left central zone (CZ) with extension into the left ejaculatory duct and left seminal vesicle.

Patient receives intensity-modulated radiotherapy.

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Case information

rID: 73247
Published: 18th Jan 2020
Last edited: 16th Jul 2020
Inclusion in quiz mode: Included

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