A Rare Cause of Cryptorchidism: Recognizing Persistent Müllerian Duct Syndrome

Persistent Müllerian duct syndrome (PMDS) represents a rare and intricate condition in medical genetics and urology, characterized by the presence of Müllerian duct derivatives — such as the uterus and fallopian tubes — in individuals who are phenotypically male with a 46, XY karyotype. This disorder stems primarily from mutations affecting the anti-Müllerian hormone (AMH) gene or its receptor, AMHR2, both critical components in sexual differentiation during embryogenesis. Normally, AMH prompts regression of the Müllerian ducts in male embryos, ensuring typical male internal genital anatomy. Disruptions in this signaling cascade result in the persistence of female reproductive structures alongside normally developed male gonads, posing complex diagnostic and therapeutic challenges.

Typically, presentation of PMDS involves cryptorchidism, inguinal hernias, or transverse testicular ectopia, where both testes descend or are located on the same side of the scrotum — a highly unusual anatomical configuration. Due to proximity and shared vasculature between Müllerian and Wolffian structures, surgical intervention necessitates extreme caution to prevent compromising fertility or damaging vital reproductive ducts. Preservation of reproductive function is paramount, given the risk of infertility arising from inadvertent injury during excision of persistent Müllerian structures.

Recently, a compelling case study led by Jeffrey T. White and colleagues at the University of Louisville School of Medicine shed new light on the diagnostic strategies and surgical management of PMDS accompanied by transverse testicular ectopia. The subject, a 4-month-old male infant, presented clinically with left cryptorchidism and the unexpected finding of two testes palpated within the right hemiscrotum. Advanced imaging modalities including preoperative scrotal ultrasound and pelvic MRI without contrast confirmed the suspicions of transverse testicular ectopia and revealed hypoplastic Müllerian remnants.

During laparoscopic exploration, the surgical team observed bilateral testes alongside hypoplastic uterine and fallopian tube structures, characteristic of PMDS pathology. Intraoperative biopsies were performed to exclude malignancy and detect any abnormalities pertaining to disorders of sexual development. Notably, the surgical approach preserved Müllerian structures instead of radical removal, prioritizing maintenance of fertility potential. Both testes were meticulously repositioned and fixed within their respective scrotal compartments to optimize chances for normative testicular function and to mitigate future complications such as malignancy or infertility.

Genomic analysis played a pivotal role in confirming the diagnosis. Genetic sequencing identified two novel mutations in the AMHR2 gene: a maternally inherited c.322A>C mutation and a paternally inherited c.658G>C mutation. These mutations expand the existing mutational landscape of PMDS and underscore the importance of molecular diagnostics in guiding clinical decision-making. Understanding the genetic underpinnings not only clarifies disease pathogenesis but also facilitates informed genetic counseling for affected families, alerting them to reproductive risks and possible transmission patterns.

This case illustrates a paradigm shift towards fertility-sparing methodologies in the treatment of PMDS. The close anatomical and vascular interrelations between Müllerian and Wolffian structures demand surgical strategies that balance excision of persistent female ducts with preservation of essential male reproductive anatomy. The nuanced approach seen in this instance — favoring conservation rather than complete removal of Müllerian derivatives — may herald improved outcomes in terms of fertility preservation and psychological well-being.

Moreover, the identification of these novel AMHR2 mutations contributes crucial data to the broader scientific dialogue about PMDS genetics. Each newly characterized mutation enriches our understanding of genotype-phenotype correlations and the molecular mechanisms driving aberrant sexual differentiation. Such insights could eventually inspire targeted therapies, novel diagnostic biomarkers, or preventative strategies, reinforcing the translational potential of genetic research in rare developmental disorders.

Imaging technologies such as scrotal ultrasonography and MRI remain indispensable tools in the assessment of complex genitourinary anomalies. Their non-invasive nature permits detailed visualization of internal pelvic organs, guiding surgical planning while reducing intraoperative risks. The integration of high-resolution imaging with genetic testing forms a multidimensional diagnostic algorithm that enhances accuracy, reduces uncertainty, and tailors individualized treatment plans.

As researchers continue to explore the etiology and management of PMDS, interdisciplinary collaboration between geneticists, urologists, radiologists, and pediatric surgeons is vital. Combining expertise from these domains fosters comprehensive care for patients with this rare syndrome, optimizing functional and psychosocial outcomes through precision medicine.

The reported findings also emphasize the necessity for long-term follow-up and surveillance of PMDS patients, given the potential for malignancies associated with undescended or ectopic testes. Regular monitoring, coupled with fertility assessments, will further elucidate the natural history of PMDS, informing guidelines for monitoring and intervention across age groups.

Ultimately, this case study enriches our grasp of a rare congenital anomaly, illustrating how cutting-edge genetic analyses combined with minimally invasive surgical techniques can converge to improve patient care. It embodies a promising step towards more refined, fertility-conscious therapies that respect the delicate balance of reproductive anatomy in disorders of sexual development.

News Publication Date: 30-Dec-2025

Web References: http://dx.doi.org/10.1002/uro2.70046