Teaching Case

A 20-year-old male presented to the emergency department with the chief complaint of left lower abdominal pain. There was no significant history. The physical examination of the patient showed well-formed external genitalia, phallus, and urethra. The patient had an empty scrotum with non-palpable testis and no surgical scars.

The CT abdomen showed left distal ureteric junction calculus (Figure 1) in 3.5 mm with proximal obstructive grade I hydroureteronephrosis. Further, multiplanar, multi-echo 3T magnetic resonance imaging (MRI) was done, and it was indicative of bilateral empty scrotal sacs (Figure 2). There was a bilaterally undescended, small-sized testis in the pelvis above the level of the sacroiliac joints. Seminal vesicles were severely atrophied (Figure 3a). The prostate was well-demarcated (Figure 4). Müllerian duct structures had a rudimentary uterus with a cervix with two small fibrotic ovaries. The uterus and cervix measured 15 x 21 x 32 mm and 18 mm, respectively. The endocervical canal (Figure 3b) was seen in continuation with the left vas deferens and opens into the prostatic urethra (Figure 5). The features were suggestive of persistent Müllerian duct syndrome (PMDS) on the left side of the pelvis.

PMDS, alternatively termed internal pseudo-hermaphroditism, is characterised by the presence of a uterus, fallopian tubes, and the upper 1/3rd of the vagina [1]. The Müllerian and Wolffian ducts exist in an adult human foetus at 7 weeks of conception. Towards the completion of the seventh week of pregnancy, the testis in the male embryo begins to differentiate. MIF (Müllerian-inhibiting factor), dihydrotestosterone, and testosterone regulate normal sex differentiation. The presence of Müllerian duct derivatives, which occur due to either a deficit in the intrauterine release of Müllerian-inhibiting factor (MIF), also referred to as anti-Müllerian hormone (AMH), induced by genetic mutation in chromosome 19 (type 1 PMDS, accountable for 45%), or inadequate AMH type II receptor (AMHR2) function due to mutation in chromosome 12 (type 2 PMDS, accountable for 40%), is the hallmark of PMDS [2]. Testosterone stimulates the division of the Wolffian ducts into the seminal vesicles, vas deferens, and epididymis [3]. Male external genitalia are differentiated by dihydrotestosterone.

The typical presenting condition of PMDS is primary infertility, which may result from cryptorchidism [4], as seen in our patient. Patients with PMDS have a typical development of additional sexual characteristics, including external genitalia, similar to our report (Figure 6). The current reported patient had completely developed additional sexual traits. Since AMH levels are known to be undetectable beyond puberty, they were not measured.

The diagnosis of PMDS is straightforward in males with normal external genitalia when an extended tubular formation is visualised behind the bladder on CT scans [5]. Because MRI has a higher soft-tissue contrast and a remarkable anatomical capacity to distinguish between the organs of the pelvis and the complicated structures in PMDS, it is the preferred modality [6] over USG or CT scans, as supported by our individual.

The simultaneous presence of testicular and ovarian tissue in an individual is characteristic of ovatestis, a true hermaphrodite condition. In terms of the gonad’s location, ovotestis was categorized by Krob et al. (1994) [7] and Auchus and Chang (2010) [8] as follows: lateral (20%), bilateral (3%), and unilateral ovotestis (50%). Our patient had bilateral ovotestis (Figure 7).

Teaching Points

The current case report highlights that PMDS is a rare condition occasionally encountered in men with a normal phenotype but with the presence of internal Müllerian duct structures. Imaging tools such as MRI have been highly valuable in identifying PMDS patients.