In the male embryo’s, sexual differentiation is initiated during 7th week of gestation. The sex determining region Y (SRY) protein activates male transcription factors that cause the bipotential cells to differentiate and proliferate into the testis. Sertoli cells of the testis produce Mullerian Inhibiting substance (MIS), which causes regression of the mullerian ducts by the 10th week of gestation. Hence, decreased production of MIS, inappropriate timing of production and MIS receptor defect can all lead to persistence of the mullerian duct. The cranial end of the mullerian duct remains as appendix testis and the caudal end as the prostatic utricle in normal males (
1). Some authors have used the terms mullerian duct remnant (MDR) and mullerian duct cyst interchangeably. However, although the two have similar embryological origins, the clinical presentation is often different.
Mullerian duct cysts present at the 3rd to 4th decade, whereas prostatic utricles are common in the 1st to 2nd decades of life. Mullerian duct cysts do not communicate with the prostatic urethra, but are connected to the verumontanum by a thin stalk. Unlike utricular cysts, the Mullerian duct cyst is not typically associated with other congenital abnormalities of the urinary tract. Very rarely these may be associated with ipsilateral renal agenesis (
2). > 90% of utricular cysts are associated with hypospadias or disorders of sexual differentiation and 60-70% with bilateral cryptorchidism. Utricle cysts are small, tubular and do not extend above the base of the prostate. mullerian duct cysts are round or oval in configuration, often large and extend well above the base of the prostate ( 3- 5).
A prevalence of 1-5% (
3) has been reported for Mullerian duct cysts, but symptomatic presentation is very rare. The clinical presentation is varied, including urinary frequency, urinary urgency, dysuria, urinary obstruction, hematuria, and pelvic pain. A case of malignant transformation in a 15 year boy has been reported5. Other differential diagnosis of deep pelvic cysts in the male includes seminal vesicle cyst (Zinner’s syndrome, a triad of mullerian duct abnormality comprising of unilateral renal agenesis, ipsilateral seminal vesicle cyst, and ejaculatory duct obstruction), ejaculatory duct cyst, prostatic cyst or abscess, urachal cyst, bladder diverticulum, hydatid disease, and intrapelvic neoplasm. The presence of a large cystic lesion and a short ureteral bud with renal agenesis led us to suspect PUJ in an ectopic pelvic kidney in our patient. MRI has been reported to be useful in the diagnosis of mullerian duct cyst by showing signal characterization of the mucus or hemorrhagic cystic component. An MRI in this patient would have helped achieve a proper pre-op diagnosis.
Treatment is indicated in symptomatic individuals and to prevent long-term complications. Both open surgical techniques and minimally invasive approaches have been described to treat mullerian duct remnants. Surgical management of prostatic utricles is challenging due to their deep location in the pelvis and close relation to important surrounding structures. Endoscopic treatment has been limited to unroofing infected and obstructed cysts. Many different open surgical approaches have been described to excise mullerian duct remnants including transperitoneal, retropubic or suprapubic extravesical, transvesical transtrigonal, posterior sagittal transanorectal, anterior sagittal transanorectal, perineal, and posterior pararectal approaches. Recently Laparoscopic and Robot assisted excision has been utilized for excision of mullerian duct cysts and remnants. It offers the advantage of a clear and magnified view of the deep pelvic structures that cannot be obtained with an open approach, enabling precise dissection with less blood loss and reduced incidence of injury to the surrounding structures (vas, ureters, nerves and urethra) (
6, 7). However, port placement and instrument manipulation could be challenging in large cysts, which tend to fill the pelvis and extend into the lower abdomen as in the present case.