A 19 year old patient presents with primary amenorrhoea. She has well developed breasts and axillary and pubic hair. Uterus and vagina are absent. The diagnosis is most likely:
**Core Concept**
The patient's presentation of primary amenorrhoea with normal secondary sexual characteristics but absent uterus and vagina suggests a disorder of sex development (DSD) involving the development of the Müllerian ducts. This involves the absence or abnormal development of the female internal and external genitalia.
**Why the Correct Answer is Right**
The correct diagnosis is Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome, a rare condition characterized by the congenital absence of the uterus and vagina, but with normal ovaries and secondary sexual characteristics. This is due to a failure of the Müllerian ducts to develop, resulting in the absence of the uterus and upper part of the vagina. The ovaries and external genitalia develop normally, leading to normal secondary sexual characteristics.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not a recognized diagnosis for primary amenorrhoea with absent uterus and vagina.
* **Option B:** Androgen insensitivity syndrome (AIS) typically presents with undervirilized external genitalia and absence of pubic and axillary hair, which does not match this patient's presentation.
* **Option C:** Congenital adrenal hyperplasia (CAH) often presents with virilized external genitalia and ambiguous genitalia, which is not consistent with this patient's presentation.
**Clinical Pearl / High-Yield Fact**
Mayer-Rokitansky-Küster-Hauser syndrome is a rare condition that affects approximately 1 in 4,500 to 1 in 5,000 females, and is often associated with other chromosomal abnormalities or genetic syndromes.
**Correct Answer:** .