Are there imaging signs of extraprostatic extension?
Yes, there is a broad capsular contact.
What are the signs of seminal vesicle invasion?
There is homogenous moderate hypointensity on T2w images along the ejaculatory ducts above the prostate and within the inferior portions of both seminal vesicles with a corresponding hypointense signal on ADC.
Why do the diffusion-weighted images (DWI) not help in this case?
This is likely due to androgen deprivation therapy.
Biparametric MRI of the prostate bpMRI
Findings:
Quality: no major artefacts
Prostate size: 42 x 38 x 40 mm (CC x AP x ML) ≈33 mL
Haemorrhage: none
Peripheral zone (PZ): diffusely hypointense bilaterally, especially posterior zone from base to apex, there is some residual heterogeneous signal in the apical anterior zones
Transition zone (TZ): some BPH nodules in the anterior transition zone, otherwise diffusely hypointense, especially within the posterior transition zone with indistinct margins of the pseudocapsule
Prostate margin: broad capsular contact
Neurovascular bundles: probably involved
Seminal vesicles: extension of T2w hypointensity and some diffusion restriction along the ejaculatory ducts above the base and within the seminal vesicles suggestive of seminal vesicle invasion
Lymph nodes: oval external iliac lymph nodes (up to 5 mm size, fatty hilum, smooth margins)
Pelvic bones: small lesion in the right femoral head very likely a bone island, no definite signs of bony metastasis
Impression:
Histologically proven prostate cancer with infiltration of both lobes especially posterior peripheral and transition zones (basal to apical) with the involvement of the central zone.
An extraprostatic extension is likely.
Probable invasion of both seminal vesicles.
MRI putative stage: cT3bNxMx