Prostate and periprostate cysts: a challenging diagnosis

Transcription

1 Prostate and periprostate cysts: a challenging diagnosis Poster No.: C-1642 Congress: ECR 2014 Type: Educational Exhibit Authors: J. F. Madureira Cordeiro, V. Garriga, J. Corral Rubio, S Bolivar, R. Contreras Chacon, A. Tanasa, F. Novell Teixido, X. Pruna ; Granollers/ES, Santa Maria de Palautordera/ES, 3 4 Badalona/ES, Sabadell/ES Keywords: Diverticula, Cysts, Congenital, Observer performance, Localisation, Diagnostic procedure, Ultrasound, MR, Pelvis, Genital / Reproductive system male, Abdomen DOI: /ecr2014/C-1642 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 49

2 Learning objectives Review of cystic prostatic lesions seen in our department, that may be encountered when performed transrectal prostate US or MRI for varied indications. Description of both US and MRI normal prostate anatomy appearance as well as prostatic and adjacent structures cystic lesions. Recognize pitfalls that may mimic the cystic pathology. Background Although their uncommon and uncertain origin, prostate and periprostate cysts are challenging diagnostic abnormalities. Since the accurate diagnosis depends mainly on the anatomic location of the cysts, understanding the embryologic development and normal anatomy of the lower male genitourinary tract can be helpful in the evaluation and approach for developing a differential diagnosis. PROSTATIC CYSTS 1. MIDLINE CYSTS: 1.1 Utricle cysts 1.2 Mullerian duct cysts 2. PARAMEDIAN CYSTS: 2.1 Ejaculatory duct cysts 3. LATERAL CYSTS: 3.1 Prostatic retention cysts 3.2 Cystic degeneration of Benign Prostatic Hypertrophy 3.3 Prostatic Abscess Page 2 of 49

3 3.4 Cavitary Prostatitis PERIPROSTATIC CYSTS 1. Seminal vesicle cysts 2. Vas deferens cysts MIMICS OF PROSTATIC AND PERIPROSTATIC CYSTS 1. Defect resulting from TURP 2. Bladder Diverticula 3. Ureterocele and Ectopic insertion of the ureter 4. Foley's catheter cuff in the prostatic urethra 5. Prominent seminal vesicles Findings and procedure details EMBRYOLOGIC DEVELOPMENT The prostate gland, as well as the urinary bladder, arise from the urogenital sinus, an endodermal derivative, by the 3rd fetal month. Small epithelial buds form on the posterior side of the urogenital sinus on both sides of the verumontanum, and these penetrate the sunrounding mesenchyme to form the prostate. Initially, embryos have two pairs of genital ducts: wolffian (mesonephric) ducts müllerian (paramesonephric) ducts Both mesodermal derivatives, originate from the common urogenital fold and are important precursors to the genitourinary system development. Page 3 of 49

4 At the male pelvis, each müllerian duct lies lateral to its corresponding wolffian duct. The müllerian ducts fuse in the midline caudally. The fused caudal tip projects into the posterior wall of the urogenital sinus as a small swelling, called the müllerian tubercle. Page 4 of 49

5 Fig. 1: Primitive undifferentiated genital tract. 1- Mesonephros. 2- Müllerian duct. 3Wolffian duct. 4 - Müllerian tubercle. 5- Inguinal ligament. 6- Undifferentiated gonad. References: Thanks to Javier Corral PhD The normal development of the male genital tract is the result of the differentiation of wolffian derivatives and the involution of müllerian derivatives in response to an androgenic stimulus produced by the developing testes. The müllerian duct degenerates except for a small portion at their cranial ends that gives rise to the appendix testis and the prostatic utricle. The wolffian duct develop into the seminal vesicles, the vas deferens, the ejaculatory duct surrounded by the prostatic glands, the epididymis and the appendix of epididymis, but also to the renal collecting system and the urether. Page 5 of 49

6 Fig. 2: 3rd fetal month of differentiation in the male genital tract: 1- Appendix of epididymis. 2- Appendix testis. 3- Atrophic müllerian duct. 4- Vas deferens. 5Seminal vesicle. 6- Ejaculatory duct. 7- Prostatic Utricle. 8- Gobernaculum testis. 9Paradidymis. References: Thanks to Javier Corral PhD NORMAL ANATOMY Page 6 of 49

7 The prostate lies immediately anterior to the rectum and inferior to the bladder. The cephalic end of the prostate gland is referred to as the base and the caudal end as the apex. The prostate gland contains three glandular zones (peripheral 70%, central 25% and transitional zone 5%) and one nonglandular zone mainly anteriorly located, the fibromuscular stroma. The peripheral zone is located along the posterior, lateral, and apical portions of the prostate. The central zone is the conical portion of the gland located above the verumontanum and between the peripheral zone and the proximal urethra and transitional zone. The transitional zone is located anteriorly and laterally to the proximal urethra. The seminal vesicles are located symmetricaly just above the base of the prostate as elongated septate cystic strutures, and behind the urinary bladder. The distal portion of the vas deferens is seen as a slightly dilated tubular structure (ampulla) medial to the seminal vesicle. Page 7 of 49

8 Fig. 3: Axial (a) and sagittal (b) anatomic draws of the prostate and adjacent structures. CZ = Central zone. TZ = Transitional zone. PZ = Peripheral zone. FS = Fibromuscular stroma. SV = Seminal vesicle. VD = Vas deferens. B= Bladder. U = Urethra. References: Thanks to Javier Corral PhD. At transrectal US, the central and peripheral zones have a homogeneous echogenic appearance, whereas the anteriorly situated transitional zone is more heterogeneous. On oblique transrectal US images, the ducts of the seminal vesicles join the distal portion of the vas deferens to form the ejaculatory ducts, which drains into the prostatic urethra at the level of the verumontanum. The urethral verumontanum is located at the angle of the prostatic urethra. The verumontanum is formed by the colliculus seminalis, a mound on the posterior wall of the prostatic urethra that accounts for the "Eiffel Tower" appearance on transverse images of the prostate gland obtained at this level. Page 8 of 49

9 Fig. 4: Anatomy of the prostate and seminal vesicles at transrectal US of a 66years-old male. a-c, Axial images obtained in the craniocaudal direction show the seminal vesicle as an oblong septate cystic structure (a), the distal portion of the vas deferens also known as ampulla of the vas deferens (pink arrow) as a slightly dilated tubular structure medial to the seminal vesicles (b). c, Central zone (CZ), transitional zone (TZ) and peripheral zone (PZ) of the prostate (c). d, Sagittal image obtained in the superoinferior direction shows the peripheral zone (PZ) of the prostate with an echogenic pattern, with a rounded, hypoechoic urethra (U) in the central zone (CZ). Fibromuscular stroma (FS) located anteriorly. Normal ejaculatory duct as a small, thinwalled tubular structure (pink arrow). The position of the seminal vesicle (SV) indicates the superior orientation of the prostate. Notice, in zoomed picture, the vas deferens (pink arrow) medial to the seminal vesicles. B= Bladder. References: Hospital General de Granollers - Granollers/ES At MR imaging, the central and transitional zones together are referred to as the central gland and cannot be differentiated. The peripheral zone is typically hypointense on T1-weighted images and homogeneously hyperintense on T2- weighted images. Page 9 of 49

10 The central gland appears heterogeneously hyperintense on T2-weighted images. At MRI, the seminal vesicles are seen as elongated fluid-containing structures with thin septa. The seminal fluid demonstrates low signal intensity on T1-weighted images and high signal intensity on T2-weighted images. The intraabdominal portions of the vas deferens are seen as bilateral symmetric tubular structures with low signal intensity on both T1- and T2-weighted images. They can be traced from the internal ring of the inguinal canal to the level of the ejaculatory duct in most cases. Fig. 5: Anatomy of the prostate and seminal vesicles at 1,5 T, T2-weighted MR imaging. (a, b) Axial images shows the peripheral zone (PZ) of the prostate with Page 10 of 49

11 homogeneous hyperintensity and the central zone (CZ) with hypointensity as well as the normal hyperintense lobulated pattern of the seminal vesicles apical to the prostate (SV). (c) Coronal image shows the relationships between the prostate (P), seminal vesicles (SV) and ejaculatory duct (pink arrow). (d) Sagittal image shows the normal anatomy of the prostate and its relations with the adjacent structures: R=Rectum. B=Bladder. References: Hospital General de Granollers - Granollers/ES PROSTATIC CYSTS Prostatic cysts may be described as either intraprostatic or periprostatic cysts by their location. MR imaging and transrectal US are the most useful diagnostic tools. INTRAPROSTATIC CYSTIC LESIONS 1) MIDLINE CYSTS Utricular and müllerian duct cysts are located in the midline behind the upper half of the prostatic urethra. Although utricle and müllerian cysts are believed to be two different entities, it is difficult to differentiate them from one another on imaging studies and clinical symptoms. Both occur in the midline and, because of that, both prostatic utricle cysts and müllerian duct cysts can cause obstructive urinary symptoms, hematuria and pelvic pain. Müllerian duct cysts and prostatic utricle cysts may become infected and can contain pus or hemorrhage, which can cause confusion on imaging because the appearances overlap those of abscess and cystic tumor of the prostate. They may as well cause ejaculatory impairment by obstruction of the ejaculatory ducts in the midline. There have been case reports of müllerian duct cysts and prostatic utricle cysts containing carcinoma. 1.1) Utricle cysts Page 11 of 49

12 They are formed due to the dilatation of the prostatic utricle. There is an incomplete regression of this remnant of the mullerian duct system, during embryologic development. 1%-5% of the general male population, males under 20 years old. Midline, small cysts (8-10 mm long), pear-shaped that, unlike müllerian duct cysts, do not extend above the base of the prostate. Known to be associated with many genitourinary abnormalities such as hypospadias, unilateral renal agenesis and cryptorchidism. Distinguishable characteristics of the prostatic utricle cysts: Always in the midline. They arise from the verumontanum but they don't extend above the base of the prostate. Communicated with the prostatic urethra (unlike the mullerian duct cysts): may result in postvoid leak. On aspiration: occasionally contain spermatozoa. At transrectal US, they manifest as a midline anechoic cystic cavity posterior to the prostatic urethra. Fig. 6: Simple prostatic utricle cyst in different patients with different sizes. (a-b), Axial B-mode sonography obtained with transrectal US shows two utricle cysts (arrows) from different patiens with different sizes. (c), Sagittal B-mode image obtained with transrectal US shows another simple midline anechoic prostatic utricle cyst: teardrop sign (white arrow). Page 12 of 49

13 References: Hospital General de Granollers - Granollers/ES 1.2) Müllerian duct cysts Müllerian duct cysts are originated from the remnants of the müllerian duct as a result from focal failure of regression in utero and focal saccular dilatation of the mesonephric duct. These cysts appear as teardrop-shaped midline cysts extending above the prostate. Occasionally associated with renal agenesis with normal external genitalia. Normally asymptomatic, although they may present similar symtoms as the utricle cyts. They may also cause ejaculatory impairment by obstructing the ejaculatory duct in the midline. Features that helps distinguish müllerian duct cysts from utricle cysts: less common than the utricle cysts (prevalence in men around 1%), between ages of 20 and 40 years old. normally bigger than utricle cysts. they may originate from the region of the verumontanum usually extend above the prostate may be slightly lateral to the midline they do not communicate with the posterior urethra on aspiration: they never contain spermatozoa commonly contain calculi (thay may cause hemorrhage) at the retrovesical cavity that is not connected to the bladder. At transrectal US, these cysts look as a midline anechoic cystic cavity posterior to the urethra and may extend above the base of the prostate. However they may demonstrate increased signal, reflecting increased concentration of mucinous material, hemorrhage, or pus. Page 13 of 49

14 AT MRI, müllerian duct cysts are usually hyperintense on T2-weighted images and fatsat T2-weighted images, due to the sperm-free fluid content. Fig. 8: Prostatic müllerian duct cyst in a 44-year-old man with lower urinary tract symptoms. Axial (a) transrectal US image shows a midline anechoic cystic lesion arrising from the base of the prostate. Axial fat-sat T2-weighted MR image show a midline high-signal-intensity prostatic cyst (arrow) originating from the prostate and extending beyond the prostatic base. The lesion is located between the seminal vesicles and the urinary bladder (b). Notice that both seminal vesicles are enlarged due to possible obstruction from the cyst (small arrows). References: Hospital General de Granollers - Granollers/ES Page 14 of 49

15 Fig. 7: Complicated mullerian cyst in a 43 years-old patient with hemospermia. Axial (a) and sagittal (b) B-mode sonographic images show a midline hypoechoic mullerian duct cyst with thickened walls and hemorrhagic contained material. When patient is turned to the lateral side, notice the hemorrhagic level within the cyst (c). References: Hospital General de Granollers - Granollers/ES 2) PARAMEDIAN CYSTS 2.1) Ejaculatory duct cysts Ejaculatory duct cysts are rare. They are due to an acquired obstruction of the ejaculatory duct, but they also may be congenital. The presence of an obstructing lesion such as a stone or utricular cyst helps distinguish acquired cysts from congenital ejaculatory duct cysts. There may be a secondary obstruction with dilatation of the ipsilateral seminal vesicle. Page 15 of 49

16 They lie in a supraprostatic location along the expected course of the ejaculatory duct in the prostate, laterally close to the midline on the central zone of the prostate and posterior to the prostatic urethra. However, when they are large, they may extend cephalad to the prostate and appear to arise centrally. On aspiration: they contain fructose or normal spermatozoa, which helps distinguish these cysts from mullerian duct or prostatic utricular cysts. Commonly contain calculi. Sometimes they may contain pus or hemorrhage. Patients often present with hematospermia or dysuria. The obstructed ejaculatory duct manifests at transrectal US as a hypoechoic cystic structure that is best seen in the sagittal plane just lateral to the midline. The transrectal US features of ejaculatory duct obstruction include ejaculatory duct cyst, calcification, and dilatation, as well as seminal vesicle dilatation. Page 16 of 49

17 Fig. 9: Ejaculatory duct cyst (big pink arrow) associated with both seminal (pink arrowhead) and deferens (small pink arrow) ectasic ducts. Remarck the elongated and thickened vas deferens urethelial wall (small arrow) that corresponds to signs of inflammatory changes. All findings are related to a 54 years-old patient with recurrent prostatitis and orchiepididimitys, probably justified by the cyst at the ejaculatory duct. References: Hospital General de Granollers - Granollers/ES MR imaging can clearly demonstrate the cause of ejaculatory duct obstruction. They are of high signal intensity on T2-weighted images, but commonly contain calculi that have low signal intensity. Fig. 11: Non-complicated eyaculatory duct cyst in a 63-years-old patient. Coronal spinecho T2 image. Page 17 of 49

18 References: Hospital General de Granollers - Granollers/ES Fig. 10: Ejaculatory duct cyst in a 28-year-old man with oligospermia. Sagittal T1 spin-echo (a) and axial T2 spin-echo weighted (b) MR images show a small, highsignal-intensity oval-teardrop shape lesion (arrow) just lateral to the midline along the course of the right ejaculatory duct just posterior to the bladder neck. Coronal T2 spin-echo weigthed MRI (c) that shows high-iso-signal-intensity level inside the cyst corresponding to hemorrhagic component (arrow), a finding that is consistent with a ejaculatory duct cyst with spermatic contained material. References: Hospital General de Granollers - Granollers/ES 3) LATERAL CYSTS 3.1) Prostatic retention cysts Acquired cysts that occur more frequently with increasing age and are seen in patients with Benign Prostatic Hyperplasia (BPH), in result of obstruction of the glandular ducts, causing dilatation of the acini. Retention cysts may occur in any zone of the prostate but the pathogenesis of prostatic retention cysts is unknown. They are identical in appearance to cysts of BPH. Common in 50 to 60 years old man. Retention cysts are smooth-walled, usually round, unilocular cysts, with 1-2 cm in diameter that contain clear fluid located in the peripheral zone. Rarely cause symptoms, but symptoms of BPH are always present. On aspiration: they never contain spermatozoa. Page 18 of 49

19 The imaging diagnosis rests on their location in the peripheral zone or on lack of other evidence of BPH. Fig. 12: Prostatic retention cysts in a 60-years-old male with BPH. Axial B-mode image shows multiple cysts that contain clear fluid located in the peripheral zone (arrow). Also notice a müllerian duct cyst arrising from the verumontanum (arrowhead). References: Hospital General de Granollers - Granollers/ES 3.2) Cystic Degeneration of Benign Prostatic Hypertrophy This is the most common cystic lesion of the prostate. It's variable in size and shape and may contain haemorrhage or calculi. Patients with these cysts usually have obstructive symptoms due to BPH. They are located in the transitional zone of the prostate, along with BPH nodules. Page 19 of 49

20 As the transition zone enlarges, it compresses the central zone, and the cyst may appear to lie in the central zone. Fig. 13: Cystic degeneration in a patient of 69-years-old with Bening Prostatic Hypertrophy with enlarged transitional zone which indentation into the vesical floor. Axial B-mode that shows a simple cyst (A) located at the TZ of the prostate. Note that the TZ enlarges and compresses the central zone, which may apparently seem as if the cyst lies in the central zone. References: Hospital General de Granollers - Granollers/ES 3.3) Prostatic Abscess Prostatic abscesses are uncommon. They may form a cystic lesion anywhere in the prostate secondary to acute bacterial prostatitis (mainly caused by Escherichia coli). The diagnosis rests on the clinical picture with symptoms that include fever, chills, dysuria, urinary frequency and urgency, hematuria, and pain. Page 20 of 49

21 Transrectal US is the imaging modality of choice for a prostatic abscess, since it is the most cost-effective modality, has better contrast resolution than computed tomography or MR imaging, and is easily accessible. Transrectal US typically demonstrates hypo or anechoic areas with thin or thick walls due to surrounding edema. Fig. 14: Phlegmon and prostatic abscess in different patients. a, Sagittal TRUS shows a hypoechoic ill-defined area in the transitional zone that corresponds to a phlegmonous lesion in a 37 years-old patient with complicated protatitis (pink arrow). Also notice a small utricle cyst (pink arrowhead). b, Prostatic abscess in a 44-yearsold pacient with a background of recurrent prostatitis. Suprapubic sonograhy shows a better defined complex cystic lesion with thick walls (pink arrow). References: Hospital General de Granollers - Granollers/ES 3.4) Cavitary prostatitis Chronic prostatitis may lead to cavitary prostatitis, in which prolonged infections and fibrosis causes glandular ductal constriction and acinar dilatation. This results in a "Swiss cheese" appearance in the prostate, with multiple small cysts of various sizes scattered throughout the gland. Knowledge of the patient's clinical history is useful in these cases. Page 21 of 49

22 Fig. 15: Cavitary prostatitis in a 52-year-old man with a background of multiple prostatitis. Axial B-mode (a) and Color Doppler (b) sonography images obtained in the craniocaudal direction show a complex prostatic lesion (pink arrow), with solid and cystic component, fine septations and small puntated calcifications (pink arrowhead). c, Coronal MRI T2-weighted image obtained with a torso array coil, shows the same lesion (pink arrow) with "Swiss cheese" appearance: Variable-sized high-low signal intensity lesions. References: Hospital General de Granollers - Granollers/ES PERIPROSTATIC CYSTIC LESIONS Extraprostatic cysts arise outside the prostate from nearby structures such as the seminal vesicles and vas deferens. 1) Seminal vesicle cysts Cysts in the seminal vesicles are often discovered incidentally at some distance from the midline. Page 22 of 49

23 Seminal vesicle cysts can be congenital or acquired. Normally are due to the congenital atresia of the ejaculatory duct. Seen in males between 10 to 40-years-old. The cysts are unilateral and commonly protrude into the bladder. If very large, they may be associated with voiding difficulties. Symptoms include hematuria, hemospermia, abnormal ejaculation, post ejaculatory perineal discomfort, and unilateral epididymitis. They are often associated with ipsilateral renal agenesis. On aspiration: they contain inactive spermatozoa and sometimes hemorrhage. At transrectal US, seminal vesicle cysts manifest as anechoic masses within the seminal vesicle, or larger anechoic saccular lesions, which may arise from the pelvis and displace the bladder and other pelvic structures. Fig. 16: Seminal vesicle cyst in a 39-year-old man with hematuria and renal left hypoplasic kidney. Axial B-mode transrectal US image obtained in the craniocaudal direction shows an anechoic cyst (pink arrow) within the left seminal vesicle. References: Hospital General de Granollers - Granollers/ES Page 23 of 49

24 2) Cysts of the Vas Deferens Vas deferens cysts are located along the course of the vas deferens and superior to the prostate. Congenital abnormalities of the vas deferens are the most common finding in men with azoospermia and low ejaculation volume. Infection, obstruction, and neoplasia are possible acquired causes of vas deferens cysts. A congenital cyst of the ampulla of the vas deferens is also very rare. Fig. 17: Ejaculatory duct cyst in a 31 year-old male with oligospermia. Axial (a) and sagittal (b) B-mode US shows a right complex ampulla cyst of vas deferens (A) that could correspond to a solid node vs spermatic material retention with distal obstrution of the vas deferens and seminal vesicle (arrows). Eyaculatory duct (arrowheads). References: Hospital General de Granollers - Granollers/ES MIMICS OF PROSTATIC AND PERIPROSTATIC CYSTS It is important to notice and consider alternative diagnoses when assessing possible prostatic and periprostatic cysts. Differentiation can be made on the basis of characteristic location, contents, and association with renal or genital anomalies, but such differentiation may be difficult since they may be incidentally found at imaging of may manifest with the same lower urinary symptoms as the cysts. Page 24 of 49

25 Mimics of prostatic and periprostatic cysts are not true cysts. They are structures such as a catheter's cuff or polipoidal formations that simulate the cystical appearance and also dilatations of nearby structures. These dilatations include ureteroceles, dilatation of the prostatic urethra after transurethral resection of the prostate (TURP), bladder diverticula, dilated ectopic ureter and ureterocele. Careful review of transrectal US and MR images in multiple planes helps identify the true nature of these conditions. 1) Defect Resulting from TURP The defect is a commonly observed finding that should not be mistaken for a cystic mass. TURP is most commonly performed for symptomatic BPH and it is seen at US as a periurethral central defect. The superior portion of this defect communicates with the bladder and appears as an irregular funnel-shaped defect in the midline. Page 25 of 49

26 Fig. 18: Defect resulting from previous TURP in different patients. Axial (a) and sagittal (b) B-mode TRUS shows a dilated bladder neck and prostatic urethra resembling a midline prostatic cyst, especially on the axial image (pink arrow). Axial (c) and sagittal (d) T2-weighted MR images in another patient with TURP. Mimetizing cyst that corresponds to the TURP defect (* in picture c). Notice a small utricle cyst at the posterior bladder wall (pink arrowhead in picture d). The clue to the diagnosis is the fact that communication between the urethra and bladder is seen in multiple planes. References: Hospital General de Granollers - Granollers/ES 2) Bladder Diverticula Bladder diverticula are very common. When they extend posteriorly, they may lie alongside the prostate or seminal vesicles and might be confused with cysts of these structures. Visualization of their communication with the urinary bladder is diagnostic. Page 26 of 49

27 Fig. 19: Bladder diverticula in a 20 years-old patient with recurrent cystitis. Axial (a) and sagittal (b) suprapubic sonograhy show a paramedial cystic lesion adjacent to the prostate (P). (c), MCU fluoroscopy demonstrate two bladder diverticula (*) depending of the posterior bladder wall of the same patient. Also note that the study shows vesicouretheral right reflux (arrow). References: Hospital General de Granollers - Granollers/ES 3) Ureterocele and Ectopic Insertion of Ureter A ureterocele can mimic a periprostatic cystic lesion with its tortuous course. Also, ectopic insertion of a dilated ureter into the prostatic urethra can resemble a tubular cystic structure. Page 27 of 49

28 Fig. 21: Ureterohydronephrosis with ureterocele mimetizing a prostatic cyst in a 12 year-old boy with obstrutive urinary symptoms and pelvic pain. Axial B-mode (a) and Power-Doppler (b) suprapubic US that shows a left ureterocele with right urinary jet (pink arrow). MCU fluoroscopy (c) of the same patient shows a grade IV ureterohydronephrosis. Vascular indentation is also identified in the perimeatal urether (pink arrow). References: Hospital General de Granollers - Granollers/ES 4) Foley's catheter cuff in the inner prostatic urethra Abnormal location of Foley's cuff at the prostatic urethra can mimic a midline prostatic cyst. Page 28 of 49

29 Fig. 20: Abnormal location of Foley's cuff at the prostatic urethra which can mimic cystic prostatic lesion. Axial and sagittal images (a) obtained in the craniocaudal direction show a hyperecogenic ring, with doppler enhancement (b). References: Hospital General de Granollers - Granollers/ES 5) Prominent seminal vesicles The appearance and size of the seminal vesicles vary considerably. Sometimes they are prominent and can mimic periprostatic cysts. However, the typical convoluted appearance of the seminal vesicles and their communication with the ejaculatory ducts assist in making the correct diagnosis. Page 29 of 49

30 Fig. 22: Prominent seminal vesicles. T2-weighted axial image shows both prominent seminal vesicles due to retained sperm, that could mimic several cysts. References: Hospital General de Granollers - Granollers/ES Images for this section: Page 30 of 49

31 Fig. 1: Primitive undifferentiated genital tract. 1- Mesonephros. 2- Müllerian duct. 3Wolffian duct. 4 - Müllerian tubercle. 5- Inguinal ligament. 6- Undifferentiated gonad. Page 31 of 49

32 Fig. 2: 3rd fetal month of differentiation in the male genital tract: 1- Appendix of epididymis. 2- Appendix testis. 3- Atrophic müllerian duct. 4- Vas deferens. 5- Seminal vesicle. 6- Ejaculatory duct. 7- Prostatic Utricle. 8- Gobernaculum testis. 9- Paradidymis. Page 32 of 49

33 Fig. 3: Axial (a) and sagittal (b) anatomic draws of the prostate and adjacent structures. CZ = Central zone. TZ = Transitional zone. PZ = Peripheral zone. FS = Fibromuscular stroma. SV = Seminal vesicle. VD = Vas deferens. B= Bladder. U = Urethra. Page 33 of 49

34 Fig. 4: Anatomy of the prostate and seminal vesicles at transrectal US of a 66-years-old male. a-c, Axial images obtained in the craniocaudal direction show the seminal vesicle as an oblong septate cystic structure (a), the distal portion of the vas deferens also known as ampulla of the vas deferens (pink arrow) as a slightly dilated tubular structure medial to the seminal vesicles (b). c, Central zone (CZ), transitional zone (TZ) and peripheral zone (PZ) of the prostate (c). d, Sagittal image obtained in the superoinferior direction shows the peripheral zone (PZ) of the prostate with an echogenic pattern, with a rounded, hypoechoic urethra (U) in the central zone (CZ). Fibromuscular stroma (FS) located anteriorly. Normal ejaculatory duct as a small, thin-walled tubular structure (pink arrow). The position of the seminal vesicle (SV) indicates the superior orientation of the prostate. Notice, in zoomed picture, the vas deferens (pink arrow) medial to the seminal vesicles. B= Bladder. Page 34 of 49

35 Fig. 5: Anatomy of the prostate and seminal vesicles at 1,5 T, T2-weighted MR imaging. (a, b) Axial images shows the peripheral zone (PZ) of the prostate with homogeneous hyperintensity and the central zone (CZ) with hypointensity as well as the normal hyperintense lobulated pattern of the seminal vesicles apical to the prostate (SV). (c) Coronal image shows the relationships between the prostate (P), seminal vesicles (SV) and ejaculatory duct (pink arrow). (d) Sagittal image shows the normal anatomy of the prostate and its relations with the adjacent structures: R=Rectum. B=Bladder. Page 35 of 49

36 Fig. 6: Simple prostatic utricle cyst in different patients with different sizes. (a-b), Axial B-mode sonography obtained with transrectal US shows two utricle cysts (arrows) from different patiens with different sizes. (c), Sagittal B-mode image obtained with transrectal US shows another simple midline anechoic prostatic utricle cyst: teardrop sign (white arrow). Fig. 8: Prostatic müllerian duct cyst in a 44-year-old man with lower urinary tract symptoms. Axial (a) transrectal US image shows a midline anechoic cystic lesion arrising from the base of the prostate. Axial fat-sat T2-weighted MR image show a midline highsignal-intensity prostatic cyst (arrow) originating from the prostate and extending beyond the prostatic base. The lesion is located between the seminal vesicles and the urinary bladder (b). Notice that both seminal vesicles are enlarged due to possible obstruction from the cyst (small arrows). Page 36 of 49

37 Fig. 7: Complicated mullerian cyst in a 43 years-old patient with hemospermia. Axial (a) and sagittal (b) B-mode sonographic images show a midline hypoechoic mullerian duct cyst with thickened walls and hemorrhagic contained material. When patient is turned to the lateral side, notice the hemorrhagic level within the cyst (c). Page 37 of 49

38 Fig. 9: Ejaculatory duct cyst (big pink arrow) associated with both seminal (pink arrowhead) and deferens (small pink arrow) ectasic ducts. Remarck the elongated and thickened vas deferens urethelial wall (small arrow) that corresponds to signs of inflammatory changes. All findings are related to a 54 years-old patient with recurrent prostatitis and orchiepididimitys, probably justified by the cyst at the ejaculatory duct. Page 38 of 49

39 Fig. 11: Non-complicated eyaculatory duct cyst in a 63-years-old patient. Coronal spinecho T2 image. Page 39 of 49

40 Fig. 10: Ejaculatory duct cyst in a 28-year-old man with oligospermia. Sagittal T1 spinecho (a) and axial T2 spin-echo weighted (b) MR images show a small, high-signalintensity oval-teardrop shape lesion (arrow) just lateral to the midline along the course of the right ejaculatory duct just posterior to the bladder neck. Coronal T2 spin-echo weigthed MRI (c) that shows high-iso-signal-intensity level inside the cyst corresponding to hemorrhagic component (arrow), a finding that is consistent with a ejaculatory duct cyst with spermatic contained material. Page 40 of 49

41 Fig. 12: Prostatic retention cysts in a 60-years-old male with BPH. Axial B-mode image shows multiple cysts that contain clear fluid located in the peripheral zone (arrow). Also notice a müllerian duct cyst arrising from the verumontanum (arrowhead). Fig. 13: Cystic degeneration in a patient of 69-years-old with Bening Prostatic Hypertrophy with enlarged transitional zone which indentation into the vesical floor. Axial B-mode that shows a simple cyst (A) located at the TZ of the prostate. Note that the TZ enlarges and compresses the central zone, which may apparently seem as if the cyst lies in the central zone. Page 41 of 49

42 Fig. 14: Phlegmon and prostatic abscess in different patients. a, Sagittal TRUS shows a hypoechoic ill-defined area in the transitional zone that corresponds to a phlegmonous lesion in a 37 years-old patient with complicated protatitis (pink arrow). Also notice a small utricle cyst (pink arrowhead). b, Prostatic abscess in a 44-years-old pacient with a background of recurrent prostatitis. Suprapubic sonograhy shows a better defined complex cystic lesion with thick walls (pink arrow). Page 42 of 49

43 Fig. 15: Cavitary prostatitis in a 52-year-old man with a background of multiple prostatitis. Axial B-mode (a) and Color Doppler (b) sonography images obtained in the craniocaudal direction show a complex prostatic lesion (pink arrow), with solid and cystic component, fine septations and small puntated calcifications (pink arrowhead). c, Coronal MRI T2weighted image obtained with a torso array coil, shows the same lesion (pink arrow) with "Swiss cheese" appearance: Variable-sized high-low signal intensity lesions. Fig. 16: Seminal vesicle cyst in a 39-year-old man with hematuria and renal left hypoplasic kidney. Axial B-mode transrectal US image obtained in the craniocaudal direction shows an anechoic cyst (pink arrow) within the left seminal vesicle. Page 43 of 49

44 Fig. 17: Ejaculatory duct cyst in a 31 year-old male with oligospermia. Axial (a) and sagittal (b) B-mode US shows a right complex ampulla cyst of vas deferens (A) that could correspond to a solid node vs spermatic material retention with distal obstrution of the vas deferens and seminal vesicle (arrows). Eyaculatory duct (arrowheads). Fig. 18: Defect resulting from previous TURP in different patients. Axial (a) and sagittal (b) B-mode TRUS shows a dilated bladder neck and prostatic urethra resembling a midline prostatic cyst, especially on the axial image (pink arrow). Axial (c) and sagittal (d) T2weighted MR images in another patient with TURP. Mimetizing cyst that corresponds to the TURP defect (* in picture c). Notice a small utricle cyst at the posterior bladder wall (pink arrowhead in picture d). The clue to the diagnosis is the fact that communication between the urethra and bladder is seen in multiple planes. Page 44 of 49

45 Fig. 19: Bladder diverticula in a 20 years-old patient with recurrent cystitis. Axial (a) and sagittal (b) suprapubic sonograhy show a paramedial cystic lesion adjacent to the prostate (P). (c), MCU fluoroscopy demonstrate two bladder diverticula (*) depending of the posterior bladder wall of the same patient. Also note that the study shows vesicouretheral right reflux (arrow). Page 45 of 49

46 Fig. 20: Abnormal location of Foley's cuff at the prostatic urethra which can mimic cystic prostatic lesion. Axial and sagittal images (a) obtained in the craniocaudal direction show a hyperecogenic ring, with doppler enhancement (b). Fig. 21: Ureterohydronephrosis with ureterocele mimetizing a prostatic cyst in a 12 yearold boy with obstrutive urinary symptoms and pelvic pain. Axial B-mode (a) and PowerDoppler (b) suprapubic US that shows a left ureterocele with right urinary jet (pink arrow). MCU fluoroscopy (c) of the same patient shows a grade IV ureterohydronephrosis. Vascular indentation is also identified in the perimeatal urether (pink arrow). Page 46 of 49

47 Fig. 22: Prominent seminal vesicles. T2-weighted axial image shows both prominent seminal vesicles due to retained sperm, that could mimic several cysts. Page 47 of 49

48 Conclusion The detailed knowledge of both embryology and anatomy location, as well as the correct use of US and MRI findings in prostatic cystic pathology, allows a proper diagnose despite usual benignancy and management of these cysts. Personal information J. F. Madureira Cordeiro, Department of Radiology, FHAG - Granollers's Hospital. Granollers, Spain. V. Garriga, Department of Radiology, FHAG - Granollers's Hospital. Granollers, Spain. J. Corral, Department of General Surgery, Germans Trias i Pujol's Hospital. Badalona, Spain. S. Bolivar, Department of Radiology, FHAG - Granollers's Hospital. Granollers, Spain. R. Contreras, Department of Radiology, FHAG - Granollers's Hospital. Granollers, Spain. A. Tanasa, Department of Radiology, FHAG - Granollers's Hospital. Granollers, Spain. F. Novell, Department of Radiology, FHAG - Granollers's Hospital. Granollers, Spain. X. Pruna, Department of Radiology, FHAG - Granollers's Hospital. Granollers, Spain. References Haytham M. Shebel, Hashim M. Farg, Orpheus Kolokythas, Tarek ElDiasty. Cysts of the Lower Male Genitourinary Tract: Embryologic and Anatomic Considerations and Differential Diagnosis. RadioGraphics 2013;33: Sajjad Y. Development of the genital ducts and external genitalia in the early human embryo. J Obstet Gynaecol Res 2010;36(5): Page 48 of 49

49 McNeal JE. Regional morphology and pathology of the prostate. Am J Clin Pathol 1968;49(3): Curran S, Akin O, Agildere AM, Zhang J, Hricak H, Rademaker J. Endorectal MRI of prostatic and periprostatic cystic lesions and their mimics. AJR Am J Roentgenol 2007;188(5): McDermott VG, Meakem TJ 3rd, Stolpen AH, Schnall MD. Prostatic and periprostatic cysts: findings on MR imaging. AJR Am J Roentgenol 1995; 164(1): Ishikawa M, Okabe H, Oya T, et al. Midline prostatic cysts in healthy men: incidence and transabdominal sonographic findings. AJR Am J Roentgenol 2003;181(6): Page 49 of 49