Diagnostic Ultrasound - Abdomen and Pelvis

Focal Lesion in Prostate
○ Variable size but usually smaller (< 10 mm) than
müllerian duct cysts; does not extend above prostate
base
○ Associated with GU anomalies: Hypospadias,
undescended testes, and unilateral renal agenesis;
malignancy reported
○ Complications: Infection, hemorrhage, may cause
postvoid dribbling (communicates with urethra)
• Seminal Vesicle Cyst
○ Lateral cyst; variable size; congenital or acquired
○ Unilateral → associated with ipsilateral renal
agenesis/dysgenesis, ectopic ureteral insertion, vas
deferens agenesis
○ Bilateral → associated with autosomal dominant
polycystic kidney disease
Helpful Clues for Rare Diagnoses
• Ejaculatory Duct Cyst
○ Congenital or acquired obstruction of ejaculatory duct
○ Paramedian cyst at base, may appear midline at or just
above level of verumontanum ± intracystic calculi
○ Spermatozoa in cyst fluid
• Vas Deferens Cyst
○ Extraprostatic, superior to gland; congenital or acquired
• Other Primary Prostate Neoplasms
○ Multilocular prostatic cystadenoma
– Rare benign tumor; large multiseptated cystic pelvic
mass
○ Prostate sarcoma
– Occurs more often in younger men (35-60 years)
– Predominantly solid, heterogeneous, vascular mass;
high-grade tumors show necrosis
○ Cystic prostatic adenocarcinoma
– Very rare, 0.6% prostatic carcinomas
– Thick-walled cystic mass with mural nodularity
• Secondary Tumors of Prostate
○ Extension of periprostatic malignancy, lymphoma,
metastases
○ Bladder cancer is most common tumor to secondarily
infiltrate prostate
○ Prostate lymphoma and metastases to prostate are both
very rare
○ Prostate lymphoma is usually secondary; primary
prostatic lymphoma is exceedingly rare
○ Metastases to prostate described in melanoma, lung
cancer, and testicular cancer
Other Essential Information
• Mimics of prostatic and periprostatic cysts
○ TURP defect
○ Bladder diverticula
○ Ectopic ureteral insertion, ureterocele
○ Malpositioned Foley catheter balloon
Alternative Differential Approaches
• Cystic lesion
○ Intraprostatic
– Median: Müllerian and utricle duct cysts
– Paramedian: Ejaculatory duct cyst
– Lateral: Retention cysts, cystic degeneration of BPH
– Variable: Cystic neoplasms, abscess
○ Extraprostatic
– Seminal vesicle and vas deferens cysts
• Solid lesion
○ Central: BPH nodules, PCa
○ Peripheral: PCa, atypia, PIN, prostatitis, fibrosis/atrophy
SELECTED REFERENCES
1. Dorin RP et al: Prostate atypia: Does repeat biopsy detect clinically
significant prostate cancer? Prostate. 75(7):673-8, 2015
2. Smolski M et al: Prevalence of prostatic calcification subtypes and
association with prostate cancer. Urology. 85(1):178-81, 2015
3. Chu LC et al: Prostatic stromal neoplasms: differential diagnosis of cystic and
solid prostatic and periprostatic masses. AJR Am J Roentgenol.
200(6):W571-80, 2013
4. Shebel HM et al: Cysts of the lower male genitourinary tract: embryologic
and anatomic considerations and differential diagnosis. Radiographics.
33(4):1125-43, 2013
5. Schull A et al: Imaging in lower urinary tract infections. Diagn Interv Imaging.
93(6):500-8, 2012
6. Galosi AB et al: Cystic lesions of the prostate gland: an ultrasound
classification with pathological correlation. J Urol. 181(2):647-57, 2009
7. Curran S et al: Endorectal MRI of prostatic and periprostatic cystic lesions
and their mimics. AJR Am J Roentgenol. 188(5):1373-9, 2007
Differential Diagnoses: Prostate
Benign Prostatic Hyperplasia (BPH)
Nodules
Benign Prostatic Hyperplasia (BPH)
Nodules
(Left) Transverse TRUS image
shows a well-defined
relatively homogeneous
hyperechoic nodule in the
right transition zone (TZ)
consistent with a benign
prostatic hypertrophy nodule.
Calcifications ſt are seen in
the periurethral region and
along the surgical capsule.
(Right) Transverse transrectal
ultrasound (TRUS) shows
multiple small cystic lesions
within the enlarged TZ, most
consistent with retention cysts
ſt. A larger anechoic, simple
cyst in the left TZ likely
represents cystic degeneration
of a BPH nodule .
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