Diagnostic Ultrasound - Abdomen and Pelvis

Prostatic Hyperplasia
TERMINOLOGY
Abbreviations
• Benign prostatic hyperplasia (BPH)
Synonyms
• Prostatism; glandular and stromal hyperplasia
• Hyperplasia is correct term since BPH is characterized by
increased number of stromal and glandular cells (not
hypertrophy, which means increase in size)
Definitions
• BPH reserved for histopathological pattern of smooth
muscle and epithelial cell proliferation in TZ and
periurethral glands
• Prostatism historically applied to almost all symptoms of
micturition disorder in older men
○ Term implies prostate as cause of problem, which may
not be the case (e.g., neurologic abnormalities)
• Lower urinary tract symptoms (LUTS) applies to any patient
with urinary symptoms, regardless of age or sex; does not
specify underlying etiology
○ Storage LUTS: Frequency, urgency, nocturia
○ Voiding LUTS: Hesitancy, straining, slow stream,
intermittent or interrupted flow, terminal dribbling,
sensation of incomplete emptying
• BPE: Benign prostate enlargement: Usually presumptive
diagnosis based on prostate size
• BPO: Benign prostate obstruction: Enlarged gland with
obstruction that has been proven by urodynamics
• BOO: Bladder outlet obstruction: Generic term for any
cause of subvesical obstruction, including BPO
IMAGING
General Features
• Best diagnostic clue
○ Enlarged prostate with nodular enlargement in
transition zone &/or periurethral region
• Size
○ Normally the size of walnut or golf ball, ~ 20-30 g
○ May be as large as 500 g
• Morphology
○ Inverted conical shape with base at urethrovesical
junction and apex at urogenital diaphragm
○ Lobular configuration was previously used but distinct
lobes do not exist
– Currently used only in context of BPH → lateral &/or
median lobe enlargement
– Replaced by zonal anatomy with morphologic,
functional, and pathologic significance
○ Prostate is divided into glandular zones and single
stromal zone (anterior fibromuscular stroma)
– Peripheral zone (PZ): ~ 70% normal glandular prostate
□ Extends from base to apex along posterolateral
aspect and surrounds distal urethra
– Central zone (CZ): ~ 25% normal glandular prostate
□ Cone-shaped with widest portion making majority
of prostatic base, surrounds ejaculatory ducts
– Transition zone (TZ): ~ 5% normal glandular prostate
□ 2 separate glands immediately external to
preprostatic urethra (from bladder neck to
verumontanum)
– Periurethral glands: < 1% normal glandular prostate
□ Glands entirely contained within smooth muscle of
preprostatic sphincter
– Historically, "inner gland" refers to periurethral glands
and TZ, and "outer gland" refers to CZ and PZ
□ In radiology, "central gland" refers to periurethral
glands, TZ, and CZ; correlates to imaging findings
– Origin of BPH is confined to periurethral glands & TZ
□ Volumetric contribution of TZ and CZ changes with
age → enlarged TZ compresses CZ
– Pseudocapsule ("surgical capsule"): Visible boundary
between central gland and PZ
– "Median lobe" seen as an intraluminal bladder
component of BPH; may originate from TZ or
periurethral glands
Radiographic Findings
• IVP
○ Elevated bladder floor with medially lifted distal ureters
yield J-shaped or fishhook ureters
CT Findings
• NECT
○ Enlarged prostate ± calcification
– Enlarged "median lobe" may protrude into bladder
lumen.
• CECT
○ Enlarged prostate with mass effect on bladder base
MR Findings
• T1WI
○ Enlarged prostate
• T2WI
○ Heterogeneous T2 signal within TZ: Varied appearance
correlates to variable histologic composition
– BPH nodules show different signal behaviors
depending on epithelial and stromal components
– BPH characterized by septation of individual nodules,
which can be seen as T2 dark rim
– Classic BPH nodule = round or oval-shaped lesion with
well-defined T2 dark rim
○ Difficult to distinguish BPH from central gland cancer
– Look for "erased charcoal" sign suggestive of
carcinoma
• DWI
○ BPH nodules may show restricted diffusion
• T1WI C+
○ Does not reliably differentiate BPH nodule from cancer
Ultrasonographic Findings
• Grayscale ultrasound
○ Prostate ultrasound most commonly used for transrectal
ultrasound (TRUS)-guided biopsies and volume
estimation
○ Estimate prostate volume using prolate ellipsoid
formula: Width x height x length x 0.52
– 1 cc of prostate tissue ~ 1 gram
○ On TRUS, normal prostate is homogeneous with
relatively more hyperechoic peripheral zone
Diagnoses: Urinary Tract
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