A 22-year-old woman has primary amenorrhea. Examination shows normal female external genitalia, blind vaginal pouch, absent uterus, normal breast development, and bilateral inguinal masses. Karyotype is 46,XY. What is the MOST likely diagnosis?

• A Turner syndrome
• B Congenital adrenal hyperplasia
• C Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome
• D Complete androgen insensitivity syndrome (CAIS) ✓

Explanation

The triad of normal female external genitalia, absent uterus, blind vaginal pouch, normal breast development, and bilateral inguinal masses (undescended testes) with 46,XY karyotype is pathognomonic for Complete Androgen Insensitivity Syndrome (CAIS). The body is genetically male but completely unable to respond to androgens, resulting in female phenotype development under estrogen influence. Gonads are undescended testes that should be removed after puberty due to malignancy risk (~3–5%). MRKH has 46,XX karyotype with absent uterus.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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