Androgen insensitivity syndrome

Clinical History

Primary amenorrhoea in a 16-year-old patient.

Imaging Findings

Pelvic MRI showed a missing uterus and ovaries with a blind ending vagina (Fig. 1). Abnormal structures, which morphologically closely resembled testes, were found located in both inguinal canals. These structures were hypointense on T1-weighted images and had an intermediate signal intensity on T2- weighted images (Fig. 2a, b).
The cytogenetic analysis revealed the kariotype of 46, XY. Bilateral laparoscopic gonadectomy was performed. The histopathology revealed the absence of germ cells and epididymis hypoplasia. No malignant evidence was found. The cytogenetics, histological and radiological findings are compatible with androgen insensitivity syndrome (AIS). Oestrogen replacement, augmentation mammaplasty and psychological therapy were prescribed.

Discussion

Androgen insensitivity syndrome (AIS), also known as the testicular feminisation, is a disorder caused by a mutation of the gene encoding the androgen receptor (AR; Xq11-q12). The syndrome is inherited in an X-linked recessive pattern. The complete androgen-insensitivity-syndrome is named Morris syndrome affecting up to 5 per 100, 000 people who are genetically male. Patients with Morris syndrome are genotypically male with a female phenotype (male pseudohermaphroditism) and they have primary amenorrhea and bilateral cryptorchidism [1, 2].

Ultrasonography (US) is the imaging modality of choice for the evaluation of patients with primary amenorrhea. The radiographic findings that permit a presumptive diagnosis of AIS include absent or rudimentary uterus and ovaries with blind ending vagina and bilateral cryptorchidism [3, 4]. MRI of the pelvis was performed to confirm the diagnosis and exclude other coexisting congenital abnormalities.

The undescended testes often produce oestradiol and have increased incidence of malignancy (seminoma and gonadoblastoma), accordingly, bilateral gonadectomy is recommended. The treatment should be undertaken by a multidisciplinary team and based on reinforcement of sexual identity, gonadectomy to avoid gonad tumours in later life, and appropriate sex-hormone replacement therapy. The prognosis is good if the testicular tissue is removed at the appropriate time [5].

Differential Diagnosis List

Final Diagnosis

Androgen insensitivity syndrome

URL:	https://www.eurorad.org/case/10316
DOI:	10.1594/EURORAD/CASE.10316
ISSN:	1563-4086