Prostate cancer - extraprostatic extension

Case contributed by Dr Joachim Feger

Presentation

Elevated prostate-specific antigen (PSA): 9.1 ng/mL. Free PSA: 11%.

Patient Data

Age: 65 years
Gender: Male

Findings:

Quality:  mild geometric distortion on DWI, does not compromise diagnostic confidence

Prostate size:    50 x 34 x 60 mm (CC x AP x ML) ≈ 53 mL, PSA density ≈ 0.17 ng/mL2

Hemorrhage:  none

Peripheral zone (PZ):  uniform hyperintense signal with two focal findings as below

Focal lesion #1:

  • Location:  right apical/midglandular posterolateral peripheral zone (RAM-PZpl), visible on axial images (ima 10-12), sagittal images (ima 20)
  • Lesion size:  18 x 10 x 17 mm
  • T2w:  circumscribed, homogenous moderate hypointense focus - category 5/5
  • DWI:  markedly hyperintense on DWI (b1000) and markedly hypointense on ADC focus - category 5/5
  • DCE:  focal early enhancement - positive

Focal lesion #2:

  • Location:  right basal  posterolateral peripheral zone (RB-PZpl), on axial images (ima 15), sagittal images (ima 20)
  • Lesion size:  8 x 7 x 8 mm
  • T2w:  circumscribed, homogenous moderate hypointense focus - category 4/5
  • DWI:  markedly hyperintense on DWI (b1000) and markedly hypointense on ADC focus - category 4/5
  • DCE:  focal early enhancement - positive

Transition zone (TZ):  moderate heterogeneity, multiple BPH nodules and a focal finding as below:

Focal lesion #3:

  • Location:  left mid gland anterior transition zone (LM-TZa), on axial images (ima 11-13)
  • T2w:  heterogeneous low signal intensity with obscured margins - category 3/5
  • DWI:  isointense on DWI (b1000) and markedly hypointense on ADC - category 3/5
  • DCE:  focal early enhancement - positive

Prostate margin:  lesion #1 with broad capsular contact (≈ 17 mm) along with some irregularity, lesion #2 also with capsular contact

Lesion overall PI-RADS category:  5

Neurovascular bundles:  adjacent to lesion #1 and lesion #2

Seminal vesicles:  not involved

Lymph nodes:  multiple small oval iliac lymph nodes (up to 8 mm size, fatty hilum, smooth margins)

Pelvic bones: a severe case of right hip osteoarthritis, no signs of bony metastasis

 

Impression:

Very highly and highly suspicious lesions of the right apical/mid gland and basal, posterolateral peripheral zones (PZpl) with capsular contact - PI-RADS 5.

A further questionable finding of the left transition zone - PI-RADS 3.

MRI putative stage: cT3aNxMx.

Prostate biopsy was recommended.

Annotated image

Key findings

Key images:

Focal lesion #1: PI-RADS category 5/5 (red arrows)

  • large (≥ 15mm) circumscribed, homogenous moderate hypointense focus, markedly hyperintense in DWI and markedly hypointense in ADC (red arrows) with early enhancement on DCE
  • located in the right apical/midglandular posterolateral peripheral zone (RAM-PZpl)

Focal lesion #2: PI-RADS category 4/5 (blue arrowheads)

  • small (<15mm) circumscribed, homogenous moderate hypointense focus, markedly hyperintense in DWI and markedly hypointense in ADC (blue arrowheads) with early enhancement on DCE (not shown)
  • located in the right basal  posterolateral peripheral zone (RB-PZpl) 

Focal lesion #3: PI-RADS category 3/5 (green arrowheads)

  • low signal intensity with obscured margins, isointense on DWI and markedly hypointense on ADC (green arrowheads)
  • located in the left basal/midglandular transition zone

 

MRI

MR in-bore biopsy

After patient preparation and positioning and acquisition of planning sequences, the suspicious lesion in the right apical/midglandular posterolateral zone (RM-PZpl), as well as the questionable finding in the left mid gland anterior transition zone (LM-TZa), are re-identified on the images, marked and locked with the navigation software.

Two biopsy cores were obtained from the lesion in the right posterolateral zone (RM-PZpl) and one biopsy core from the lesion in the left anterior transition zone (LM-TZa), in both cases with a 150cm 18G biopsy needle.

The images also nicely depict some challenges involved with the MR in-bore biopsy procedure. In this one can see a significant displacement of the prostate, while directing the needle guide.  This is probably the result of the needle guide being introduced to deep into the rectum.

Case Discussion

This case shows a typical PI-RADS 5 lesion of the right posterolateral peripheral zone (PZpl), a smaller PI-RADS 4 lesion further basal as well as a PI-RADS 3 finding in the left transition zone.

The case also demonstrates, target planning and documentation while doing an MR in-bore biopsy with two different targets.

Histology of the MR in-bore biopsy of the right posterolateral peripheral zone revealed a continuous infiltrate of an acinar adenocarcinoma (modified Gleason Score 4+5=9, G2b, high grade) within the two cores. The core taken from the left transitional zone turned out to be chronic prostatitis.

The patient underwent robot-assisted, laparoscopic, radical prostatovesiculectomy with bilateral pelvic lymphadenectomy about 7 months after mpMRI.

Final histology of the prostatovesiculectomy preparation revealed poorly differentiated acinar adenocarcinoma in both lobes with 95% of the tumor located on the right side. There was right-sided extraprostatic extension, nonfocal infiltration of the periprostatic fatty tissue and perineural invasion.

Grading G3, Gleason score 5+3=8, WHO grade 4.

Seminal vesicles were free of tumor cells.

One of seven lymph nodes of the right pelvic nodes was positive for tumor cells.

Tumor classification: pT3a pN1(1/16) M0 R0.

The patient also has been receiving adjuvant intensity-modulated radiotherapy and androgen deprivation therapy (ADT).

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Case information

rID: 73014
Published: 10th Jan 2020
Last edited: 3rd May 2020
Inclusion in quiz mode: Included

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