Persistence of Müllerian ducts in male pseudohermaphroditism, and its relationship to cryptorchidism

Persistent Müllerian Duct Syndrome with Supernumerary Testicles Due to a Novel Homozygous Variant in the AMHR2 Gene and Literature Review

Introduction: Persistent Müllerian duct syndrome (PMDS) is a rare disorder of sex development (DSD) caused by mutations in the genes coding anti-Müllerian hormone (AMH) or the AMH receptor, characterized by the persistence of Müllerian derivatives, the uterus and/or fallopian tubes, in otherwise normally virilized boys. Testicular regression syndrome is common in PMDS, yet the association with supernumerary testis has been reported in only two patients where genetic testing was not performed. Method: Thus, we report an individual with this particular association caused by a previously unreported homozygous variant in the AMHR2 gene to enable future genotype-phenotype correlations in this rare disorder. In addition, a search of PMDS associated with congenital anomalies reported in the literature was performed to provide a comprehensive overview of this pathology. Results: We present the case of a 13-year-old boy with a history of bilateral cryptorchidism. Two attempts of right orchidopexy were performed at the age of 4 and 5 years. At that time, exploratory laparoscopy identified an intra-abdominal left testicle. In addition, a fibrous structure extending from the left intra-abdominal testicle to the deep inguinal ring (Müllerian duct remnants) and a medially located abdominal mass, bilaterally fixated to the parietal peritoneum (uterine remnant), were detected. The left testicular biopsy revealed immature prepubertal testicular tissue. The uterine remnant was dissected and removed and the left orchidopexy was performed. The karyotype was 46, XY without other numerical or structural chromosomal abnormalities. Reinterventions on the left testicle were performed at the age of 9 and 12 years when a testicular remnant was identified in the left inguinal canal and removed. Three months after left orchidectomy, ultrasound followed by abdominopelvic MRI identified a structure resembling a testis in the left inguinal area. Another surgical exploration was performed, and a mass located outside (lateral) the inguinal canal was found. A biopsy from the suspected mass was performed. The histopathologic examination showed characteristics of immature prepubertal testis. The patient was later referred to our clinic with the suspicion of DSD. Serum AMH and inhibin B were normal. Therefore, the diagnosis of PMDS was suspected. Genetic testing was performed using next-generation sequencing in a gene panel that included AMH and AMHR2 genes. A homozygous variant classified as likely pathogenic in the AMHR2 gene was identified but remains unreported in the literature (NC_000012.11:g.53823315T>C in exon 8 of the AMHR2 gene). Conclusions: A high degree of suspicion and awareness is needed to diagnose this condition in order to avoid iterative surgery. The coexistence of two extremely rare conditions (PMDS and supernumerary testes) has been reported previously in only two patients, yet the association could have a common pathophysiologic background. Our case, reporting a novel AMHR2 variant, highlights the importance of genetic testing in these individuals in order to elucidate a possible genotype-phenotype correlation.

The curious case of testicular descent: factors controlling testicular descent with a note on cryptorchidism

Background

The testicular descent is a uniquely complex process depending upon multiple factors like growth and reorganisation of the specific gonadal ligaments, hormones, etc., which interplay with each other. Though an unambiguous event, it is still laced with incredulity since the data interpretation were intermingled between different species creating more ambiguity in certain aspects of this process. In order to understand the aetiopathology of cryptorchidism the extensive study of the factors controlling the descent is necessitous.

Main body

Though testes originate in the abdomen, they migrate to an extra abdominal site the scrotum, which makes it vulnerable to pathological conditions associated with the descent. The hormones that play vital role in the first phase of descent are insulin-like hormone 3 (INSL3), Anti-müllerian hormone as well as testosterone, whereas androgens, genitofemoral nerve and its neurotransmitter calcitonin gene-related peptide (CGRP) influence the second phase. Despite the vast research regarding the complex nexus of events involving the descent there are disparities among the cross species studies. However all these discrepancies make testicular descent yet again fascinating and perplexing. Our aim is to provide a comprehensive review including recent advances which provides thorough coverage of anatomical and hormonal factors in the descent as well as cryptorchidism.

Conclusion

Though our understanding on testicular descent has evolved over the decades there still has obscurity surrounding it and the studies on the factors responsible for descent are becoming more intense with the time. Our knowledge on many factors such as INSL3 and CGRP is more established now; however, on the other hand the role of androgens still remains speculative. As the knowledge and understanding of the biological process of testicular descent increases it will pave ways to new treatment plans to treat cryptorchidism more effectively.

Persistent Mullerian Duct Syndrome: A Single-Center Experience

Context:

Persistent Mullerian duct syndrome (PMDS) is a rare disorder. It is a type of male pseudohermaphroditism, usually presenting as “Hernia Uteri Inguinalis”.

Aims:

This study aims to present our experience of PMDS, over a 7-year period.

Settings and Design:

Our center is a tertiary care facility, situated in Tamil Nadu, a southern state of India.

Subjects and Methods:

This is a retrospective study. The study period was from 2007 to 2015. Seven cases presented during that period. The difficulties in diagnosis, treatment options discussed, along with a review of literature are presented.

Results:

Seven cases of PMDS presented over 8 years. Only four were diagnosed preoperatively. Mullerian remnants were excised in five cases.

Conclusions:

PMDS is rare. Orchiopexy should be the goal of treatment.

Perspectives in Pediatric Pathology, Chapter 5. Gonadal Dysgenesis

One of the most challenging areas in pediatric testicular pathology is the appropriate understanding and pathological diagnosis of disorders of sexual development (DSD), and in particular, the issue of gonadal dysgenesis. Here we present the main concepts necessary for their understanding and appropriate classification, with extensive genetic correlations.

The regulation of testicular descent and the effects of cryptorchidism

The first half of this review examines the boundary between endocrinology and embryonic development, with the aim of highlighting the way hormones and signaling systems regulate the complex morphological changes to enable the intra-abdominal fetal testes to reach the scrotum. The genitoinguinal ligament, or gubernaculum, first enlarges to hold the testis near the groin, and then it develops limb-bud-like properties and migrates across the pubic region to reach the scrotum. Recent advances show key roles for insulin-like hormone 3 in the first step, with androgen and the genitofemoral nerve involved in the second step. The mammary line may also be involved in initiating the migration. The key events in early postnatal germ cell development are then reviewed because there is mounting evidence for this to be crucial in preventing infertility and malignancy later in life. We review the recent advances in what is known about the etiology of cryptorchidism and summarize the syndromes where a specific molecular cause has been found. Finally, we cover the recent literature on timing of surgery, the issues around acquired cryptorchidism, and the limited role of hormone therapy. We conclude with some observations about the differences between animal models and baby boys with cryptorchidism.

Anti-müllerian hormone: a valuable addition to the toolbox of the pediatric endocrinologist

Anti-Müllerian hormone (AMH), secreted by immature Sertoli cells, provokes the regression of male fetal Müllerian ducts. FSH stimulates AMH production; during puberty, AMH is downregulated by intratesticular testosterone and meiotic germ cells. In boys, AMH determination is useful in the clinical setting. Serum AMH, which is low in infants with congenital central hypogonadism, increases with FSH treatment. AMH is also low in patients with primary hypogonadism, for instance in Down syndrome, from early postnatal life and in Klinefelter syndrome from midpuberty. In boys with nonpalpable gonads, AMH determination, without the need for a stimulation test, is useful to distinguish between bilaterally abdominal gonads and anorchism. In patients with disorders of sex development (DSD), serum AMH determination helps as a first line test to orientate the etiologic diagnosis: low AMH is indicative of dysgenetic DSD whereas normal AMH is suggestive of androgen synthesis or action defects. Finally, in patients with persistent Müllerian duct syndrome (PMDS), undetectable serum AMH drives the genetic search to mutations in the AMH gene, whereas normal or high AMH is indicative of an end organ defect due to AMH receptor gene defects.

A single base pair mutation encoding a premature stop codon in the MIS type II receptor is responsible for canine persistent Müllerian duct syndrome

Müllerian inhibiting substance (MIS), a secreted glycoprotein in the transforming growth factor-beta family of growth factors, mediates regression of the Müllerian ducts during embryonic sex differentiation in males. In persistent Müllerian duct syndrome (PMDS), rather than undergoing involution, the Müllerian ducts persist in males, giving rise to the uterus, fallopian tubes, and upper vagina. Genetic defects in MIS or its receptor (MISRII) have been identified in patients with PMDS. The phenotype in the canine model of PMDS derived from the miniature schnauzer breed is strikingly similar to that of human patients. In this model, PMDS is inherited as a sex-limited autosomal recessive trait. Previous studies indicated that a defect in the MIS receptor or its downstream signaling pathway was likely to be causative of the canine syndrome. In this study, the canine PMDS phenotype and clinical sequelae are described in detail. Affected and unaffected members of this pedigree are genotyped, identifying a single base pair substitution in MISRII that introduces a stop codon in exon 3. The homozygous mutation terminates translation at 80 amino acids, eliminating much of the extracellular domain and the entire transmembrane and intracellular signaling domains. Findings in this model could enable insights to be garnered from correlation of detailed clinical descriptions with molecular defects, which are not otherwise possible in the human syndrome.

Anti-Müllerian hormone in men with normal and reduced sperm concentration and men with maldescended testes

OBJECTIVE

To evaluate serum anti-Müllerian hormone (AMH) in well-characterized men with normal and reduced sperm concentration and in men with a history of or persistent maldescended testes as a possible clinical marker of male factor infertility and/or maldescended testes.

DESIGN

Retrospective analysis of 199 men selected from our database (Androbase).

SETTING

The university-based Institute of Reproductive Medicine.

PATIENT(S)

One hundred eight men with normal and 60 men with reduced sperm concentration without known cause of infertility and additionally 31 infertile men with current or former maldescended testes were evaluated.

INTERVENTION(S)

Serum AMH was analyzed by an in-house ELISA.

MAIN OUTCOME MEASURE(S)

Hormone and semen parameters were compared and correlated with AMH.

RESULT(S)

No significant differences were found in AMH levels. Only in men with maldescended testes did AMH correlate negatively with FSH and positively with testicular volume and sperm concentration. No correlations between AMH and LH or testosterone (T) were found.

CONCLUSION(S)

Anti-Müllerian hormone serum levels are not significantly affected by impaired spermatogenesis in general but are correlated with spermatogenic parameters in men with current or former maldescended testes. Therefore, AMH measurement does not improve clinical routine diagnostics but should be evaluated further in patients with maldescended testes. Anti-Müllerian hormone might serve as a marker of Sertoli cell number, function, and/or maturation in these men.

Testicular descent, cryptorchidism and inguinal hernia: the Melbourne perspective

Cryptorchidism is the commonest congenital genitourinary anomaly in males and results when the testis does not descend into its normal intrascrotal position during development. In full-term infants, the incidence is approximately 3% at birth. Cryptorchidism results in several abnormalities, including attenuated spermatogenesis, infertility and a greater risk of malignancy. The normal mechanism of testicular descent appears to be multi-staged, with various anatomical factors and hormonal influences, but the exact process is still unclear. In this article we review the current theories of normal testicular descent, with a focus on the hormones and anatomical factors, and current treatments for undescended testis.

A case of transverse testicular ectopia with müllerian duct remnant

Transverse testicular ectopia (TTE) associated with persistent müllerian duct (PMD) is a rare genitourinary anomaly. The authors report a case with a review of the literature and stress the importance of careful physical examination and ultrasonography in making a correct preoperative diagnosis of TTE. One should be careful not to miss the tiny PMD structure at the operation. Transseptal orchidopexy is the surgical treatment of choice.

Scanning electron microscopy shows inhibited gubernacular development in relation to undescended testes in oestrogen-treated mice

The morphological relationship between transabdominal testicular descent and the 'swelling reaction' of the gubernaculum was investigated in oestrogen-treated fetal mice by using scanning electron microscopy (scanning EM). In addition, flutamide was also administered to pregnant mice to determine whether androgens cause gubernacular growth and transabdominal testicular descent in offspring. In oestrogen-treated fetal mice, scanning EM showed that both the gubernacular 'swelling reaction' and transabdominal testicular descent were inhibited, in addition to inhibition of Müllerian duct regression. The gubernaculum showed a flat, thin bulb (widest diameter 0.25 +/- 0.04 mm) and an elongated cord (1.28 +/- 0.41 mm) after oestrogen treatment in utero, which was significantly different in appearance from that in normal control mice (width 0.44 mm +/- 0.06 mm, p < 0.001; length 0.27 +/- 0.19 mm, p < 0.0001). However, flutamide-treated mice showed much more normal gubernacular enlargement and transabdominal testicular descent. The width of the gubernacular bulb after flutamide exposure was 0.44 +/- 0.05 mm, which was comparable to that in control animals; the length of the intra-abdominal gubernaculum (0.44 +/- 0.15 mm) was slightly longer than in controls (p < 0.02). These results suggest that both the swelling reaction of the gubernaculum and transabdominal testicular migration are blocked by prenatal exposure to oestrogen. However, oestrogen exposure of the fetus does not block the swelling reaction of the gubernaculum by acting as an antiandrogen.

Surgical and genetic aspects of persistent müllerian duct syndrome

Persistent müllerian duct syndrome (PMDS) is characterized by the presence of a uterus, cervix, and fallopian tubes in an otherwise normally differentiated 46.XY male. During embryogenesis, regression of müllerian structures in normal males is mediated by antimüllerian hormone (AMH), also called müllerian inhibiting substance (MIS), produced by fetal Sertoli's cells. PMDS has been attributed to deficient AMH activity or to abnormalities in the AMH receptor. The authors report on two patients with PMDS in whom the abnormalities were discovered during surgery for inguinal hernia and cryptorchidism. During the initial operations in each case, testicular biopsies were obtained, and the gonads and müllerian elements were replaced in the pelvis. A second operative procedure, performed several months later, included proximal salpingectomies with dissection of the vasa deferentia on pedicles of myometrium. This permitted excision of the vestigial uterine corpus, leaving a tiny remnant of cervix with the vasa deferentia. The testes were further mobilized so that bilateral orchidopexies could be completed. In the first case, a molecular abnormality was present at position 377 of the first exon of the AMH gene. Thymine replaced cytosine, which altered a CGG arginine codon to a TGG tryptophan codon, rendering the AMH molecule unstable. The molecular abnormality in the first case differs from the first abnormality in AMH reported by Knebelmann et al, thus indicating heterogeneity in this condition. The molecular basis for deficient AMH activity in the second patient has not yet been defined. No molecular abnormalities were found in the exons of this patient's AMH gene.

The fetal rat gubernaculum contains higher levels of androgen receptor than does the postnatal gubernaculum

The androgen receptor of the rat gubernaculum was measured by a sensitive immunoblotting technique from day 19 of fetal development to day 20 of postnatal development. In relative terms (densitometric units/microgram. protein), it was found that the amount of the gubernacular androgen receptor decreased dramatically from fetal to postnatal development, coincident with the transition of the gubernaculum from a tissue primarily composed of undifferentiated mesenchymal cells in the fetus to a tissue that is primarily made up of muscle during postnatal development. We conclude that the undifferentiated mesenchyme of the fetal gubernaculum is a primary target of androgen action.

17 alpha-Hydroxylase deficiency with persistence of müllerian ducts in a genotypic male and paradoxical aldosterone secretion

We report a case of congenital adrenal hyperplasia due to 17 alpha-hydroxylase deficiency in a Chinese genotypic male patient. Despite the male genotype, normal female external genitalia were present and with the introduction of cyclical oestrogen therapy withdrawal bleeding occurred, confirming the presence of functional endometrial tissue. We believe this to be the first report of persistent Mullerian duct structures in a genotypic male with 17 alpha-hydroxylase deficiency. It could be explained by either impaired secretion or impaired action of anti-Mullerian hormone. Further, contrary to the usual finding of suppressed aldosterone secretion, this patient had measurable levels of plasma aldosterone.

Radiological findings in three cases of persistent müllerian duct syndrome

We report three cases of persistent Müllerian duct syndrome, which is a rare form of inherited male pseudohermaphroditism characterized by the presence of a uterus and tubes in otherwise normally virilized 46,XY males. We emphasize the usefulness of ultrasonographic study of the pelvis and inguinal areas in the preoperative diagnosis, which is difficult. We recommend that ultrasound be performed routinely in bilaterally cryptorchid patients.

Persistent müllerian duct syndrome with transverse testicular ectopia and spermatogenesis

Normal male sexual differentiation is dependent on at least 2 factors: 1) testosterone and 2) müllerian inhibiting factor. The absence of müllerian inhibiting factor is responsible for a rare form of male pseudohermaphroditism, the persistent müllerian duct syndrome or hernia uteri inguinale. Patients with this syndrome present with persistent müllerian structures and the syndrome may be associated with transverse testicular ectopia. Additionally, most patients have azoospermia. We report a case of persistent müllerian duct syndrome with transverse testicular ectopia in which sperm are documented in the ejaculate.

Persistent müllerian duct syndrome

Persistent müllerian syndrome is rare. A case of phenotypically normal male with persistent müllerian structures that consisted of a bicornuate uterus, fallopian tubes, and upper third of the vagina is reported. These unusual structures were found in association with bilateral cryptorchidism and a right inguinal hernia, and were diagnosed while repairing the hernia in the neonatal period. The uterus and fallopian tubes were removed via laparotomy when the child was eighteen months old; at the same time a bilateral orchiopexy was performed. To avoid damage to the vas deferens, which lay in closely to the müllerian structures and could not be separated from the vaginal wall, a small segment of the upper third of the vagina was retained. The testicles, although normal on pathologic examination, have shown poor response to hormonal stimulation with human chorionic gonadotropin. Long-term follow-up for these patients is necessary because they have an increased risk of testicular tumors developing.

Persistent müllerian duct syndrome in a man with transverse testicular ectopia

A 33-year-old Pakistani man with transverse testicular ectopia underwent surgery for repair of a left inguinal hernia. At operation a uterine structure with attached vasa deferentia was found in the left inguinal area and it was removed. Transverse testicular ectopia has been reported previously in association with the persistent müllerian duct syndrome. A deficiency of activity of a müllerian inhibiting substance during gestation is believed to be responsible for this syndrome. Most patients usually are sterile. Cloning of the gene for a müllerian inhibiting substance should permit studies of the pathogenesis of the persistent müllerian duct syndrome.

Persistence of müllerian ducts in male rabbits passively immunized against bovine anti-müllerian hormone during fetal life

A female rabbit was immunized against purified bovine AMH and mated. Booster injections were given at Day 8 of pregnancy to ensure a high titer of anti-AMH antibodies at the time the rabbit fetal testis begins to produce AMH. In three consecutive litters, the immunized female produced a total of 12 males, 9 of which had persistent Müllerian duct derivatives. No other significant abnormalities were detected in these animals, which were compared to the offspring of a control saline-injected female. In particular, testicular morphology was normal in most animals, and serum FSH levels did not differ from controls. This experimental model lends no support to the hypothesis that AMH controls extra-Müllerian events of male sex differentiation, nor that of the existence of a regulatory mechanism for synthesis of AMH by Sertoli cells, but it does not definitely exclude these possibilities, inasmuch as our tentative conclusions are based upon study of only one immunized female.

Mullerian inhibiting substance: a fetal hormone with surgical implications

Mullerian Inhibiting Substance (MIS) is secreted from the fetal (and postnatal) testis and is known to cause regression of the Mullerian ducts, the anlage of the fallopian tubes, uterus and upper vagina. It is a large glycoprotein hormone, the action of which appears to be modulated by sex steroids: mainly testosterone in mammals and oestrogen in birds. Recent evidence has raised the possibility that its action may be to diminish cell surface phosphorylation and thereby change the direction of differentiation of the Mullerian duct towards regression. Other suspected functions for MIS include control of testicular descent and inhibition of malignant tumours of the female genital tract.

Persistent Müllerian duct syndrome. Review and report of 3 cases

Three cases of persistent Müllerian duct syndrome are reported. All were phenotypically and karyotypically male but with persistent duct remnants. Problems encountered in management and surgery are discussed.