Robot-Assisted Laparoscopic Management of Persistent Mullerian Duct Structures in a Male Infant: A Novel Technique

Abstract

Background: Persistent Mullerian duct syndrome (PMDS) is a rare disorder of sexual development that results in the presence of internal female reproductive structures in male children who are otherwise phenotypically normal. The removal of the Mullerian structures is suggested, as they pose a risk for future malignancy.

Case Presentation: In this study, we present the case of a 14-month-old male infant who initially presented with bilateral nonpalpable undescended testes and was later diagnosed with PMDS. The effective removal of the Mullerian structures and bilateral orchiopexy was performed using robot-assisted laparoscopy, a novel approach for such a scenario.

Conclusion: To our knowledge, this is the first report of using robotics for management of this syndrome.

Introduction

Persistent Mullerian duct syndrome (PMDS) is a rarely reported disorder of sexual development. Male children with this condition develop internal female reproductive organs (specifically a uterus and fallopian tubes) in addition to their normal male reproductive organs. The uterus and fallopian tubes develop from the Mullerian duct, which normally regresses in utero in male children. However, in male children with PMDS, the Mullerian duct does not regress either because of a deficiency in anti-Mullerian hormone (AMH; PMDS type 1) or the inability of AMH to bind to its target receptor (PMDS type 2). This disorder follows an autosomal recessive mode of inheritance and although the exact prevalence rate is unknown, as of 2014, only 262 cases of PMDS have been reported.¹

Diagnosis requires a low index of suspicion and is typically seen as a constellation of other key physical examination findings, most notably cryptorchidism, inguinal hernias, and abnormalities of the penile urethra. In fact, the majority of PMDS is discovered incidentally while operating for undescended testes or inguinal hernia, with 80% of cases presenting with some combination of uni- or bilateral undescended testis with uni- or bilateral inguinal hernia. However, if two of the three key physical examination findings aforementioned are present, these findings should trigger a thorough work-up. This begins with karyotype testing. Although imaging may help elucidate the anatomy, either ultrasonography or MRI can detect persistent Mullerian structures, although there is no clear advantage of one over the other because of the lack of comparable studies.¹ Diagnostic laparoscopy is widely recognized as the most accurate diagnostic method for impalpable testes (97% sensitivity).^1,2 The close association of cryptorchidism with PMDS thus makes laparoscopy the method of choice for both diagnosis and treatment of PMDS.

Early recognition is crucial with prompt removal, preferably within 2 years of age as up to 8.4% of male children will develop Mullerian malignancies.¹ Surgical removal presents challenging dissection from a known shortening of the internal spermatic vessels and vas deferens with increased tortuosity. This dissection is delicate as the deferential vessels serve as the remaining vascular pedicle for the testis when staged placement of the testis within the scrotum is desired. As such, inadvertent damage to the deferential vessels, which occurs in 6% of cases, is the most feared complication. The aim of surgical management is to preserve the testis (and future fertility potential), placing it in normal scrotal position and excising the abnormal Mullerian structures (eliminating future malignant conversion), when possible. This has historically proven difficult as surgical removal may result in ischemic and or traumatic damage to the deferential blood supply. Thus, the uterus and fallopian tubes have historically been left in situ. With more contemporary management, open intervention is rarely performed as laparoscopic procedures have gained popularity as they reduce the risk of inadvertent damage to the vas deferens. However, in this study we report a novel approach to removing persistent Mullerian structures using robot-assisted laparoscopy as we believe it offers benefits over other techniques.

Case Presentation

A 14-month-old male infant presented to pediatric urology clinic for evaluation of bilateral undescended testes. His medical and surgical histories were unremarkable aside from prior circumcision. No penile urethral abnormality was noted on physical examination with a normal appearing phallus and scrotum with bilateral nonpalpable undescended testes. He was subsequently consented for karyotype testing and laparoscopic bilateral orchiopexy. Our patient was taken to the operative suite 6 weeks later for bilateral laparoscopic orchiopexy after preoperative karyotype testing revealed that he was genetically 46 X,Y. Laparoscopic exploration revealed the presence of persistent Mullerian structures (Fig. 1). After further discussion with his family, we changed our intended laparoscopic orchiopexy to diagnostic laparoscopy with a genitourogram to further delineate the anatomy and better counsel the family regarding the new findings and treatment options. Retrograde genitourogram revealed a small opening at the mid-verumontanum consistent with the urethral utricle and a vaginal remnant communicating with a dextro-rotated uterus demonstrated on fluoroscopy (Fig. 2). Because of this unexpected news and its impact on the family, we concluded the diagnostic laparoscopy without intervening to allow the family the necessary time needed to come to a treatment decision with which they were comfortable.

FIG. 1.

Laparoscopic view of patient's pelvic structures with clearly visible female internal reproductive organs characteristic of persistent Mullerian duct syndrome.

FIG. 2.

Retrograde genitourogram demonstrating a dextro-rotated uterus and fallopian tube.

The patient was brought back to the operative suite 8 weeks later for planned robot-assisted laparoscopic surgery. Using the DaVinci Xi robotic surgical platform (Intuitive Surgical, Sunnyvale, CA), bilateral primary orchiopexy, with preservation of internal spermatic vessels, complete excision of persistent Mullerian structures, and bilateral testicular biopsies were done without any complications intraoperatively (Fig. 3). He enjoyed an uneventful postoperative course and was subsequently discharged home on the same day. Postoperative evaluation 16 months later revealed both testicles were viable; however, the right one was in a low scrotal position and the left one was retracted in a suprascrotal position. He recently underwent uneventful left side scrotal orchiopexy with placing the testicle in low scrotal position.

FIG. 3.

Both testes with preserved internal spermatic vessels after robot-assisted dissection.

Discussion

PMDS is an exceedingly rare genetic disorder that causes the Mullerian duct to not regress in male children during in utero development, resulting in them being born with internal female reproductive structures. As was the case in the patient presented earlier, PMDS is associated with cryptorchidism and is commonly an incidental finding during the laparoscopic diagnosis or treatment of impalpable testes. The removal of the Mullerian structures has been deemed somewhat controversial, as some authors propose that there is no additional risk to retaining the structures and, furthermore, their removal risks damage to the testes and vas deferens.³ However, more recent reports have estimated that up to 8.4% of PMDS patients will develop malignancies associated with retained Mullerian structures.⁴ If the structures are not removed, patients need to be followed on a long-term basis to screen for malignant growth. Overall, there is consistent evidence to support the prompt excision of Mullerian structures, when possible, ideally before the age of 2.

Currently, laparoscopic procedures are favored for the treatment of PMDS and there are several options for managing the condition. The uterus can be split longitudinally to be used to add length during orchiopexy or the Mullerian structures can be removed. However, they often may be left in situ because of the difficult nature of their removal and the precision necessary to avoid damage to deferential vascular supply. Although laparoscopy has long been the preferred surgical management of PMDS, we believe that there may be a benefit to using robot-assisted laparoscopic techniques. To our knowledge, this is the first case in which robot-assisted laparoscopy was utilized to remove persistent Mullerian structures and also performing bilateral orchiopexy simultaneously.

We believe the robot-assisted approach allowed for delicate dissection and better tissue handling because of several advantages inherent to the technology. Robot-assisted laparoscopy allows for seven degrees of freedom and full 360° motion compared with the six degrees of freedom offered by traditional laparoscopy in addition to tremor filtering. The real superiority, however, of robot-assisted surgery is in the observation. The DaVinci Xi surgical system allows up to 12 × magnification and three-dimensional high-definition vision that allows for better depth perception when deep within the pelvis. Although overall outcomes do not differ between laparoscopic and robot-assisted approaches, mean blood loss, conversion rates, and hospital stays favor robotic surgery even to an extent that it may offset the greatest drawback of robotics—costs.⁵ Taken together, the increased dexterity and enhanced view allows the surgeon to perform more meticulous and precise dissection with confidence. It is precisely the reason the DaVinci Xi as utilized in this case and, we believe, aided in removal of the Mullerian structures while preserving vascularity for bilateral orchiopexy. This enabled precise dissection while preserving future fertility, as well as simultaneously decreasing the risk of future malignant conversion of Mullerian remnants. We hope to see the robot-assisted laparoscopic technique employed to a greater extent in the future and plan to use this as our standard approach in all future cases of PMDS. With time, we believe surgical correction of PMDS through the robotic approach will become yet another standard in pediatric urology akin to pyeloplasty or ureteroureterostomy because of its safety in the infant population. In one of the largest contemporary studies in pediatric robot-assisted surgery assessing pediatric robotic pyeloplasty, the technique was safely used in children as young as 6 months with no significant differences in complications or failure rates in infants compared with older children, with those authors advocating for the adaptation of robot-assisted surgery for the entire pediatric patient population.⁶

Conclusion

PMDS is a rare disorder of sexual development that is characterized by the presence of typical male reproductive structures, with the additional presence of Mullerian duct structures. The Mullerian structures should be removed to prevent future

malignant changes. Laparoscopic procedures are currently preferred in the management of PMDS with various treatment options available. We, however, employed a novel approach using robot-assisted laparoscopy. Such an approach provides outstanding view and delicate dissection allowing for safe removal of the Mullerian structures.

Abbreviations Used

AMH

anti-Mullerian hormone

PMDS

persistent Mullerian duct syndrome

MRI

magnetic resonance imaging

Disclosure Statement

No competing financial interests exist.

Funding Information

No funding was dedicated to this project.

Cite this article as: Pearce A, Crigger C, Hajiran A, Al-Omar O (2020) Robot-assisted laparoscopic management of persistent Mullerian duct structures in a male infant: A novel technique, Journal of Endourology Case Reports 6:1, 35–38, DOI: 10.1089/cren.2019.0079.