MPCs are uncommon and predominantly benign, often referred to as “do not touch” lesions. These cysts arise from diverse anatomic structures and are sometimes associated with genitourinary abnormalities or symptoms.Although transrectal ultrasound and CT imaging play supportive roles, pelvic MRI remains the preferred diagnostic tool, providing noninvasive and detailed visualization of the prostate gland and associated structures.

MPCs can be categorized into two main groups: intraprostatic and extraprostatic cysts.

A-Intraprostatic cysts : 

When considering the location, Intraprostatic cysts can be further classified into median cysts, paramedian cysts, and lateral cysts.

Median intraprostatic MPCs prompt the hypotheses of utricle or müllerian duct cysts.

Müllerian duct cysts : [1,2]

• Müllerian duct cysts arise from remnants of Müllerian ducts and are more commonly identified in the 3rd or 4th decade of life.
• They do not communicate with the urethra and may contain calculi. Typically tear-shaped, these cysts extend above the prostate and may deviate slightly from the midline.They contain sperm-free brownish fluid, which is of high signal intensity on T2-weighted images. Calculi may cause hemorrhage into the cyst, which can be demonstrated on T1-weighted images. Symptomatic cases can present with urinary retention, urinary tract infections, or ejaculatory duct obstruction. Carcinoma development, while rare, remains a potential complication.
• Although the current literature presents some debate over whether Müllerian duct cysts (MDCs) and prostatic utricle cysts (PUCs) are identical or represent separate entities,recent studies distinguish Müllerian duct cysts from utricle cysts based on immunohistochemical evidence, which shows distinct embryological origins.

Fig 1: Mullerian duct cyst : 39-year-old male with a history of treated kidney stones presenting with 1-week history of left back pain. Pelvic MRI reveals an intraprostatic midline cyst (Asterisk) with a teardrop-shape on the coronal T2-weighted image (A). Axial images show an intrinsic liquid-liquid level within the cyst: the upper component (Yellow arrowhead) exhibiting water signal, while the lower component (Red arrowhead) exhibits low signal on the T2-weighted image (B) and high signal on the T1-weighted image (C), persisting after fat suppression (D). The cyst wall is thin and regular, showing no contrast enhancement on the fat-saturated post-Gadolinium T1-weighted image (E).

Prostatic Utricle Cysts [3]

• Typically diagnosed in childhood, Prostatic Utricle Cysts originate from the verumontanum and are always midline structures, measuring 8–10 mm in length.They are pear-shaped and do not extend beyond the base of the prostate, features that helps distinguish it from a mullerian duct cyst. Utricle cysts are often linked to conditions such as hypospadias, pseudohermaphroditism, and cryptorchidism.

• Müllerian duct cysts and prostatic utricle cysts are susceptible to infection, often resulting in pus accumulation. This can complicate imaging interpretation, as their presentation may closely mimic that of prostatic abscesses or cystic tumors, leading to diagnostic uncertainty.

Fig 2: Utricle cyst : axial and sagittal T2-weighted MR images ( a and d) and axial T1-weighted images showing a median intraprostatic structure, hyperintense T2 and hypointense T1.

Paramedian intraprostatic MPCs are most associated with ejaculatory duct cysts or urethral diverticulum.

Ejaculatory duct cyst[4]

• Ejaculatory duct cyst lesions point to the seminal caruncle of the prostate and are associated with dilated ipsilateral seminal vesicles.
• They appear to be cystic structures along the ejaculatory duct just lateral to the midline in the central zone of the prostate. However, when they are large, they may extend cephalad to the prostate and appear to arise centrally.
• They are of high signal intensity on T2-weighted images, but commonly contain calculi that have low signal intensity.
• Laboratory examinations of the cystic fluid contain sperm, while the Müllerian duct cyst fluid does not contain sperm.

Fig 3: Ejaculatory duct cyst : 35-year-old man with azoospermia.Transverse T2-weighted MR images show ejaculatory duct cyst (EDC) that extends from verumontanum to left of midline above prostate along course of ejaculatory duct. Hemorrhage (arrow)layering at dependent aspect of cyst is also seen.

Urethral diverticulum [5]

• Urethral diverticulum (UD) is a rare condition characterized by saccular dilatation of the urethral wall, which can be congenital (10%) or acquired (90%).It has a peak age incidence of 25–45 years.
• UD MRI will show a periurethral abnormality that can be round, partially circumferential or "saddle-bag" in shape and communicates with the urethral lumen, allowing to make a definitive diagnosis.

Fig 4: Urethral diverticulum : Midline sagittal T2-weighted MRI demonstrates hyperintense structure (arrows) located in and above posterior aspect of the prostate (p); b=bladder. Right of image is posterior.

Lateral intraprostatic MPCs include prostatic retention cysts, cystic degeneration of benign prostatic hypertrophy, abscesses, or tumors.

Prostatic retention cysts [6]

• Prostatic retention cysts typically develop in individuals in their 50s or 60s and are often asymptomatic. Commonly associated with benign prostatic hyperplasia (BPH), these cysts form due to dilatation of glandular acini caused by acquired ductal obstruction.
• They are characterized by smooth-walled,usually round cysts and can appear in any prostate zone. Diagnosis is based on their presence in the peripheral zone and the absence of other findings indicative of BPH.

Fig 5: Retention cyst : 66-year-old man with prostate cancer. Transverse T2-weighted MR images show unilocular, smooth, and thin-walled prostatic retention cyst (RC) in peripheral zone of prostate.

Cystic degeneration of benign prostatic hyperplasia (BPH): [6]

• Cystic degeneration of BPH is a common lesion arising from degenerative changes in BPH within the transitional zone of the prostate.
• These cysts often exhibit irregular shapes and variable sizes, sometimes containing hemorrhagic material or calculi. Patients with such lesions typically experience urinary obstruction symptoms linked to BPH.

Fig 6: Cystic degeneration of benign prostatic hyperplasia (BPH) : 59-year-old man with prostate cancer. Sagittal T2-weighted images show hypertrophic transition zone (TZ) indenting urinary bladder (B). Note that one of benign prostatic hyperplasia nodules (N) has a cystic component (arrows).

Fig 7: Cystic degeneration of benign prostatic hyperplasia (BPH) : 59-year-old man with prostate cancer.Transverse T2-weighted images show hypertrophic transition zone (TZ) indenting urinary bladder. Note that one of benign prostatic hyperplasia nodules (N) has a cystic component (arrows).

Prostatic abscesses [7]

• Prostatic abscesses are rare and may present as cystic lesions in any part of the prostate. Diagnosis primarily relies on clinical evaluation.
• While MRI is not typically used for this condition, an abscess should be considered when imaging reveals a cystic lesion with thickened walls, septations, or heterogeneous content, in patients with characteristic clinical symptoms.

Fig 8: Prostatic abscesses : 68-year-old man with prostate cancer and chronic prostatitis. T2-weighted coronal MR image shows multiple peripheral cystic areas (arrows, A) consistent with pathologically proven chronic prostatitis.

Cystic carcinoma[8]

• A cystic carcinoma should be suspected if the cyst grows rapidly or if it has irregular walls, irregular signal intensity, or a solid component.

Fig 9: Cystic carcinoma : 68-year-old man with mixed tumor of prostate containing high-grade ductal adenocarcinoma, with transitional cell and nonkeratinizing squamous cell differentiation. Transverse T2-weighted MR images show tumor (T) with cystic and solid components. Fluid-fluid level (arrow) is also seen at dependent portion of cystic component of tumor.

B-Extraprostatic cysts :

Extraprostatic cysts include cysts of the seminal vesicle, vas deferens, and Cowper duct.

Seminal vesicle cysts :[9]

• Seminal vesicle cysts, which develop laterally, are caused by congenital atresia of the ejaculatory duct. These cysts are typically unilateral and often extend into the bladder. Their contents are frequently hemorrhagic and contain inactive spermatozoa.

Fig 10: Seminal vesicle cyst : Sagittal T2-weighted MR images show right seminal vesicle cyst (SVC) above prostate (P).

Cysts of the Vas Deferens : [6]

• Cysts of the Vas Deferens are located superior to the prostate gland along the course of the vas deferens. On MRI,they are easily recognized and distinguished from other adjacent structures.

Fig 11: Cysts of the Vas Deferens : Bladder tumor in a 65-year-old man. Axial (a) and coronal (b) T2-weighted MR images obtained with a torso array coil show a mass (arrow) arising from the lateral bladder wall, along with incidentally discovered dilatation of the left vas deferens (arrowhead) as it courses toward the seminal vesicle (SV). u = right pelvic ureter.

Cowper gland cysts :[6]

• The Cowper gland ducts drain into the bulbous urethra, and their obstruction may lead to the formation of retention cysts. While most Cowper duct cysts are asymptomatic, larger ones may cause hematuria, urinary obstruction, or even male infertility.
• Typically, they appear at MR imaging and transrectal US as a unilocular cystic lesion at the posterior or posterolateral aspect of the posterior urethra.

Fig 12: Cowper duct cyst : 53-year-old man with prostate cancer. Cowper's duct cyst (arrows) is shown on and coronal T2-weighted MR images.

Most prostate cysts are benign and self-healing,surgical interventions especially minimally invasive treatments are recommended for symptomatic midline prostatic cysts and malignant prostatic cysts.