Differentiation between primary amenorrhea and androgen insensitivity syndrome

Patients with androgen insensitivity syndrome have male gonads and testicles. In the early embryonic period, the testicles secrete testosterone, but due to the lack of androgen receptors in the target organ cells, they are insensitive to androgen, which hinders the development of external genitalia and male secondary sexual characteristics. After puberty, the testicles develop and can secrete estrogen to produce a feminizing effect, causing breast development similar to that of women and symptoms of amenorrhea. It should be noted that it is differentiated from primary amenorrhea. Clinically, it is divided into two types: complete androgen insensitivity and partial androgen insensitivity.

Completely androgen insensitive

Clinical manifestations include primary amenorrhea, female body shape, breast development during puberty, but poor nipple development, no or sparse pubic and axillary hair, poor development of female vulva, labia majora and minora, short vagina with blind upper end, no cervix and uterus, and no menstruation during artificial cycles. The gonads may be located in the labia majora, groin, or abdominal cavity. Patients often seek medical attention due to primary amenorrhea, labia majora, or groin masses. This type of patient can be differentiated from primary amenorrhea through androgen sensitivity tests.

Partially androgen insensitive

The external genitalia may show clitoral hypertrophy or a short penis, often accompanied by hypospadias. Therefore, when patients with primary amenorrhea have a blind vagina and no uterus, the presence of androgen insensitivity syndrome should be considered. The chromosome type is XY, the follicle-stimulating hormone and luteinizing hormone in the blood are increased, and androgens are within the normal male range or increased, which is the basis for the diagnosis of this disease. This type of patient can be differentiated from primary amenorrhea through external genitalia examination and hormone level examination.