Well-defined Prostate
Cancer of Transition Zone
Jinxing Yu, MD
Professor of Radiology & Surgery
Director of Prostate Imaging & Intervention
Virginia Commonwealth University
Richmond
Introduction

A focal, homogeneous T2-hypointensity and irregular margins (erased charcoal
sign) are characteristic features of TZ PCa



It is common to have a PCa of the TZ present with atypical MR imaging
features such as

Well-defined margins

T2 inhomogeneity or hyperintensity

Diffusion restriction only present either on ADC map or DWI but not on both

Lack of rapid contrast wash-in and –out
In order to achieve high accuracy in the diagnosis of PCa


But these features are only present in 51% and 58% of TZ tumors
Radiologists must be familiar with atypical MR imaging features of TZ PCa
A biopsy proven case of PCa in TZ with well-defined margins will be presented
73-year-old man with serum PSA=5.3ng/ml
Two prior negative TRUS prostate biopsies
A
B
C
T2
ADC
DCE
Figure – PCa with well-defined margins in the left transition zone. A) Axial T2WI shows
a homogeneous, hypointense nodule (arrow) with pseudocapsule (arrowheads) in the
left TZ mimicking a benign nodule. B) ADC map shows severe diffusion restriction of
the nodule (arrow). C) DCE shows rapid contrast wash-in and -out of the nodule
(arrow). Since T2 was the dominant sequence for transition zone, the nodule was read
as PI-RADS 3 lesion. MRI/US fusion-guided biopsy confirmed PCa, Gleason score 9.
Teaching Points

Prostate cancer with ill-defined-margins are often present

The margins of some PCa may be not identified or pseudo-well-defined,
particularly for PCa seen in TZ

Likely due to compressed surrounding normal prostate tissue



Great mimics of benign hyperplastic nodules in TZ
Imaging clues for accurate diagnosis include:

Featureless appearance of the lesion (“erased charcoal sign”)

Severe diffusion restriction on both DWI and ADC map

Abnormal early enhancement with wash-out

Partial irregular margins of the lesion may be detected
If PCa of TZ still cannot be excluded after analyzing all imaging features of a
well-defined nodule, an imaging-guided biopsy of the nodule will be of benefit
to exclude potentially aggressive tumor
References

,
Kitzing YX, Prando A Varol C, Karczmar GS, Maclean F, Oto A.
Benign Conditions That Mimic Prostate Carcinoma: MR Imaging
Features with Histopathologic Correlation. RadioGraphics 2016;
36:162–175

Akin O, Sala E, Moskowitz CS, et al. Transition zone prostate cancers:
features, detection, localization, and staging at endorectal MR imaging.
Radiology 2006; 239:784–792

American College of Radiology. MR Prostate Imaging Reporting and
Data System version 2.0 [Internet]. 2015 [cited 2015 July 20]. Available
from: http://www.acr.org/Quality-Safety/Resources/PIRADS/

Li H, Sugimura K, Kaji Y, et al. Conventional MRI capabilities in the
diagnosis of prostate cancer in the transition zone. AJR Am J
Roentgenol 2006; 186(3): 729–742