Teaching Case

A 32-year-old phenotypically male patient came with complaints of low backache and vague abdominal discomfort for one year. Physical examination showed a palpable mass in the lower abdomen. Bilateral scrotal sacs were empty with normal penis, prostate and secondary sexual characters. Laboratory workup showed elevated levels of serum lactate dehydrogenase:1367.0 U/l. Serum beta-hCG and Alpha-fetoprotein were within normal limits.

A contrast-enhanced Computed Tomography (CT) of the abdomen revealed a large heterogeneously enhancing lobulated lesion in the midline of the pelvis with no evidence of calcifications within. A fluid-filled tubular structure was seen just posterior to the urinary bladder in continuity with the prostatic urethra. Both scrotal sacs were empty. Multiple enlarged homogeneously enhancing lymph nodes were seen in the retroperitoneum. Magnetic resonance imaging (MRI) of the pelvis showed a tubular structure with zonal anatomy and signal intensity of uterine tissue. The uterus was connected to a fluid-filled tubular structure representing the vagina, seen to communicate with the prostatic urethra. Neither seminal vesicles nor ovaries could be identified. Prostate appeared normal. In addition to a T2W heterogeneous lesion in the midline of the pelvis, two other well-defined oval structures resembling testes were seen. The one on the right side was hypointense on both T1W and T2W images and was seen to be encased within the pelvic lesion in its posterolateral aspect. The left side structure was hypointense on T1W and hyperintense on T2W images, close to the uterus. Few ill-defined T2W hyperintense structures were seen surrounding the left testis, which probably represents the müllerian duct derivatives. Cumulating the findings seen on CT and MRI, a diagnosis of Persistent Müllerian duct syndrome-Female type with malignant germ cell tumour of the right undescended testis and retroperitoneal lymph nodal metastasis was made.

Persistent Müllerian duct syndrome (PMDS) is a type of internal male pseudohermaphroditism characterized by the presence of Müllerian duct derivatives caused by a deficiency in the intrauterine release of Müllerian-inhibiting factor (MIF), also called Anti-Müllerian Hormone (AMH) or due to defective functioning of anti-Müllerian hormone type II receptors [1]. Fewer than 300 cases have been reported worldwide [2]. The majority of the cases of PMDS have an autosomal recessive mode of transmission, but few cases of X-linked inheritance have also been described in the literature [3]. MIF is a glycoprotein produced by the Sertoli's cells, which is responsible for the regression of Müllerian ducts in the male fetus at 8-10 weeks of gestation [4]. The gene responsible for MIF is localized on the short arm of chromosome 19 [5]. Lack of release of MIF results in a phenotypically and karyotypically male individual having both male and female reproductive organs derived from the Wolffian and Müllerian ducts, respectively.

PMDS has been described to have two anatomic variants: male form (80-90% of cases) and female form (10-20% of cases) [5]. The male form is characterized by the presence of unilateral cryptorchidism and contralateral inguinal hernia. Based on the contents of the hernia sac, it is further subdivided into Hernia uteri inguinali and crossed testicular ectopia. In Hernia uteri inguinali, the contents that herniate into the inguinal canal include the descended testis, the ipsilateral aspect of the uterus, and the ipsilateral fallopian tube. In contrast, in crossed testicular ectopia, both testes, the entire uterus, and both fallopian tubes herniate into the inguinal canal.

Primary infertility is a common presenting complaint. Usually, it is incidentally detected intraoperatively during herniorrhaphy or surgery for undescended testes. Ultrasound (USG) can reveal the contents of the scrotal and hernial sacs, and the intra-abdominal location of the undescended testes. When an elongated tubular structure is identified behind the urinary bladder on CT in a male with normal external genitalia, the diagnosis of PMDS becomes easy [6]. MRI is the modality of choice due to its higher soft-tissue contrast and its exceptional morphological ability to delineate the pelvic organs and the complex structures in PMDS, which cannot be determined on either USG or CT [7].

Persistence of the Müllerian duct remnants or an ectopic testis increases the risk for malignancy, particularly with elevated LDH levels. Intra-abdominal testes present a higher rate of malignancy than those located in the inguinal canal with an incidence of 5 to 18 % [8,9]. Among the germ cell tumours, Seminoma is the most common appearing hypointense on T2W images. MRI can characterise the nature of the lesions with germ cell tumours appearing heterogeneous on contrast images. Areas of restricted diffusion within the lesion strongly suggest malignant transformation.

The patient underwent a guided biopsy from the pelvis mass, which revealed Seminoma stage II. He received four cycles of neoadjuvant chemotherapy with Etoposide and Cisplatin, following which he underwent exploratory laparotomy with en bloc resection of bilateral gonads.