Diagnostic ultrasound ( PDFDrive )

CHAPTER 10 The Prostate and Transrectal Ultrasound 391
U
R
L
U
A
B
SV
U
C
D
E
FIG. 10.9 Prostate Cysts. (A) Degenerative retention cyst of benign
prostatic hyperplasia (BPH) (arrow). This is the most common type of cyst
seen in the prostate and has no clinical signiicance. Note the marked asymmetry
of BPH, with the left transition zone (L) much larger than the right (R), and the
asymmetrical position of the urethra (U). (B) Utricle cyst (U) on axial view
through the prostate base. These cysts are typically in the midline and have a
distinct wall. (C) Midsagittal view shows the utricle cyst (U) with its characteristic
teardrop shape pointing toward the verumontanum (arrow). These cysts can
obstruct ejaculatory ducts and result in seminal obstruction and dilation of seminal
vesicles (SV), as in this patient. (D) Peripheral zone cyst (arrow). These cysts
are uncommon but may be so tense that they mimic the hardness of cancer
on DRE. Biopsy may be needed to prove that this is not cancer. These cysts
disappear after biopsy. (E) Utricle cyst with calciications along its wall
(arrows). This type of cyst can be related to hematospermia.
and müllerian), (3) ejaculatory duct cysts, (4) abscesses, (5) cystic
tumors, and (6) cysts related to parasitic disease (schistosomiasis,
hydatid disease). 42,43 By far, the most common cysts are parenchymal
degenerative cysts in hyperplastic nodules in the transition
zone. hese have no clinical signiicance but on occasion
can become large enough to contribute to urinary or ejaculatory
obstruction. Typically, these are seen as unilocular or thinly
septated multilocular cysts in a typical BPH nodule in the transition
zone (see Fig. 10.9A). Some patients develop atrophic dilation
of prostate ducts, which appear as 1- to 2-mm-diameter clusters
of radially oriented tubules or cysts in the peripheral zone. hese
have no signiicance (see Fig. 10.9A,B).
Retention cysts are focal cysts typically smaller than 1 cm
at the surface of the prostate and result from duct obstruction.
hey can be very tense and become palpable as a hard prostate
nodule mimicking cancer on DRE but on ultrasound appear as
a typical cyst. hey have no signiicance, but if they are palpable,
aspiration helps conirm their benign nature and avoids future
clinical concern when a hard “nodule” is again palpated at that
site (see Fig. 10.9D).