Persistent mullerian duct syndrome

Abstract Persistent Mullerian duct syndrome (PMDS) is a rare form of internal male pseudohermaphroditism in which Mullerian duct derivatives are seen in a male patient. This syndrome is characterized by the persistence of Mullerian duct derivatives (i.e. uterus, cervix, fallopian tubes and upper two thirds of vagina) in a phenotypically and karyotypically male patient. In this article we present the USG and MRI features of a case of PMDS with bilateral cryptorchidism and left sided inguinal hernia, containing the uterus and fallopian tubes.


Introduction
Persistent Mullerian duct syndrome (PMDS) is a rare form of internal male pseudohermaphroditism in which Mullerian duct derivatives are seen in a male patient. [1] The syndrome is caused either by an insuffi cient amount of Mullerian inhibiting factor (MIF) or due to insensitivity of the target organ to MIF. [2] In this article, we present the USG and MRI features of a rare case of PMDS.

Case Report
A 38-year-old man was found to have a uterus, fallopian tubes, and a gonad in the left hernial sac during herniorrhaphy. The patient developed a left scrotal sac swelling postoperatively.
On physical examination, the right scrotal sac was empty. The left scrotal sac appeared boggy. The patient was phenotypically male, with male patt ern of external genitalia and secondary sexual characteristics. The past history included primary infertility.
USG showed a well-formed uterus situated alongside the bladder and extending into the inguinal canal [ Figure 1a]. The endometrial cavity was distended with a small collection [ Figure 1b]. An oval structure with uniform internal echoes, conforming to a testis, was noted at the level of the left deep inguinal ring [ Figure 2]. The prostate and seminal vesicles were well visualized and appeared normal. The left scrotal sac showed a septate collection, consistent with a hematocele. No testis was identifi ed within the left scrotal sac. The right scrotal sac was empty. The right testis could not be identifi ed in an ectopic location.
MRI confi rmed the USG fi ndings. It showed a well-formed uterus and fallopian tubes alongside the urinary bladder and extending into the left inguinal region [ Figure 3]. A small collection was noted in the uterine cavity [ Figure 3b]. An oval structure measuring 3.7 ϫ 1.9 cm, with morphology and signal intensity consistent with a testis was detected at the level of the deep inguinal ring [ Figure 4]. A vagina-like structure was seen extending from the uterus toward the left seminal vesicle [ Figure 5]. No structure conforming to the testis was seen in the scrotal sac or in any ectopic location. The right gonadal Abstract Persistent Mullerian duct syndrome (PMDS) is a rare form of internal male pseudohermaphroditism in which Mullerian duct derivatives are seen in a male patient. This syndrome is characterized by the persistence of Mullerian duct derivatives (i.e. uterus, cervix, fallopian tubes and upper two thirds of vagina) in a phenotypically and karyotypically male patient. In this article we present the USG and MRI features of a case of PMDS with bilateral cryptorchidism and left sided inguinal hernia, containing the uterus and fallopian tubes.    Exploratory laparotomy/excision was planned for the patient subsequently. However the patient refused a second surgery.

Discussion
PMD S is a rare formof internal male pseudohermaphroditism caused by a deficiency of MIF. [2,3] Derivatives of the Mullerian duct (i.e., fallopian tubes, uterus, and the upper part of the vagina) are present in a normal genotypically and phenotypically male. PMDS patients have normal development of external genitalia and secondary sexual characteristics.
In a human fetus the Mullerian and Wolffi an ducts are both present at 7 weeks of gestation. In a male fetus, the testis diff erentiates by the end of the 7 th gestational week. Normal sex diff erentiation is controlled by testosterone, dihydrotestosterone, and MIF. Sertoli cells secrete MIF, which leads to regression of the Mullerian ducts. Testosterone has a direct eff ect on the Wolffi an ducts, and promotes their diff erentiation into the epididymis, vas deferens, and seminal vesicles. [3] Dihydrotestosterone induces male diff erentiation of external genitalia. PMDS patients have both Wolffi an and Mullerian duct structures due to a defi ciency of MIF.
Two anatomic variants of PMDS have been described, the male type and the female type. The most common variant is the male form, encountered in 80-90% of cases and characterized by unilateral cryptorchidism with a contralateral inguinal hernia. The male form of PMDS can be of two types. The fi rst type is hernia uteri inguinalis, which is usually characterized by a descended testis and herniation of the ipsilateral corner of the uterus and the ipsilateral fallopian tube into the inguinal canal. [3,4] The second type is crossed testicular ectopia, which is characterized by herniation of both testes and the entire uterus and both fallopian tubes. [3,4] The second anatomic variant of PMDS, the female form, is seen in only 10-20% of cases and is characterized by bilateral cryptorchidism, with the testes fixed within the round ligaments in an 'ovarian position' with respect to the uterus. [3,5] The gonads are fixed within the pelvis. [4] The mobility of Mullerian structures is an important factor that determines the clinical presentation. [3,4] If the uterus and fallopian tubes are mobile, they may descend into the inguinal canal during testicular descent. On the other hand, if the Mullerian structures are relatively immobile, testicular descent may be impeded. [3,4] In our case there was bilateral cryptorchidism, with a vanishing right testis. However the Mullerian structures were mobile and were found as part of the contents of the hernial sac. The left test is showed aborted descent and was located at the deep inguinal ring as part of the hernial sac, alongside the uterus and fallopian tube. Though our case is ambiguous and its categorization is debatable, in view of the mobile Mullerian structures, it probably falls into the fi rst category or the male type. However, the presence of bilateral cryptorchidism could favor its categorization into the female form of PMDS.
The risk of malignancy in an ectopic testis in a case of PMDS is similar to that in a cryptorchid testis in a healthy male. [6] Germ cell tumors have been reported in the testis, whereas tumors of the Mullerian duct derivatives are very rare. [7] Since the patients are phenotypically male, the diagnosis is usually not suspected until surgery for cryptorchidism or hernia repair.
To conclude, in a case of bilateral cryptorchidism associated with hernia, as in our case, the possibility of PMDS should be kept in mind.