A 17-year-old presents with primary amenorrhoea. Breast development is Tanner stage 4. She has no pubic or axillary hair. On examination, the vagina ends as a blind pouch. Karyotype is 46,XY. Serum testosterone is in the male range. The most likely diagnosis is:

• A Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome
• B Swyer syndrome (46,XY pure gonadal dysgenesis)
• C Complete androgen insensitivity syndrome (CAIS) ✓
• D Congenital adrenal hyperplasia (CAH)

Explanation

Complete androgen insensitivity syndrome (CAIS) is characterised by a 46,XY karyotype, testes (intra-abdominal or inguinal), normal female external genitalia, absent uterus and upper vagina, Tanner stage 3–4 breast development (due to peripheral aromatisation of testosterone to oestrogen), and absent pubic/axillary hair (due to androgen insensitivity). MRKH syndrome (46,XX, absent uterus and vagina) has normal ovaries and female body hair. Swyer syndrome has streak gonads, infantile sexual development, and requires hormone replacement for puberty induction. CAH causes virilisation with 46,XX karyotype.

Reference: Shaw's Textbook of Gynaecology, 17th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.