What is the “erased charcoal sign”?
It refers to a homogeneously T2 low-signal appearance of a lesion in the prostatic transition zone with blurred, smudged margins.
What is referred to as the “prostate pseudocapsule” or “surgical capsule”?
It is the appearance of a thin hypointense band around the transition zone even though on histological evaluation no true capsule is found.
Findings:
Quality: some geometric distortion on DWI, does not compromise diagnostic confidence
Prostate size: 42 x 40 x 40 mm (CC x AP x ML) ≈33 mL, PSA density ~0.17 ng/mL2
Haemorrhage: none
Peripheral zone (PZ): bilateral linear/wedge-shaped hypointensities, focal finding in the left posterior mid gland and basal zones as below:
Transition zone (TZ): moderate heterogeneity, some BPH nodules in the apical zone, focal finding in the left posterior mid gland and basal zones as below:
Focal lesion #1 (PZpm/pl and TZp):
- location: left mid gland and basal posterior peripheral zone (PZpm/pl) and left transition zone (TZp)
- lesion size: ~20 x 16 mm
- T2w: heterogeneous, low signal in the posteromedial peripheral zone (PZpm) and homogeneous, moderately hypointense signal in the posterior transition zone (TZp) with indistinct/obscured prostate pseudocapsule – “erased charcoal sign” – category 5/5
- DWI: focal slightly to markedly hyperintense on DWI (b1000) and markedly hypointense on ADC in the posterior transition zone (TZp) and in the posteromedial part of the peripheral zone (PZpm) - category 3/5 and 5/5, respectively
- DCE: focal early enhancement - positive
Prostate margin: capsular contact, no bulge or breach
Overall PI-RADS category: 5
Neurovascular bundles: probably not involved
Seminal vesicles: contracted, not involved
Lymph nodes: multiple small oval iliac lymph nodes (up to 6 mm size, fatty hilum, smooth margins)
Pelvic bones: no osseous metastases
Other pelvic organs: normal
Impression:
A very highly suspicious lesion in the left peripheral zone (PZpm/pl) and left posterior transition zone (TZp) - PI-RADS 5.
A prostate biopsy was recommended.