Differential Diagnosis for Primary Amenorrhea
The patient's presentation of primary amenorrhea, normal secondary sexual characteristics, and the absence of a uterus or cervix on pelvic ultrasound guides the differential diagnosis.
Single most likely diagnosis
- Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome: This condition is characterized by the congenital absence of the vagina, cervix, and uterus in individuals with a 46,XX karyotype, which fits the patient's presentation. The presence of normal ovaries and secondary sexual characteristics supports this diagnosis, as MRKH syndrome typically spares ovarian function.
Other Likely diagnoses
- Androgen Insensitivity Syndrome (AIS): Although less likely given the presence of a normal female phenotype and the specific absence of the uterus and cervix, AIS could be considered if there were any hints of androgen resistance. However, the normal development of breast, axillary, and pubic hair makes this less probable.
- Gonadal Dysgenesis: This condition involves abnormal development of the gonads and can lead to primary amenorrhea. However, it often presents with other signs such as short stature or dysmorphic features, which are not mentioned in the case.
Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Adrenal or Ovarian Tumors: Although rare, tumors could potentially cause primary amenorrhea through hormonal imbalances. The absence of symptoms like weight gain, hirsutism, or virilization makes this less likely, but it's crucial to rule out due to the potential severity.
- Pituitary or Hypothalamic Tumors: These could lead to hormonal imbalances affecting menstruation. The lack of symptoms such as headaches or visual changes makes this less probable, but given the potential severity, it's essential to consider.
Rare diagnoses
- Congenital Adrenal Hyperplasia (CAH): This is a group of inherited disorders that affect the adrenal glands, leading to hormone imbalances. While it could potentially cause primary amenorrhea, the presentation typically includes signs of androgen excess, which are not described in the case.
- Vaginal Agenesis with Functional Uterus: This is a rare condition where the vagina is underdeveloped or absent, but the uterus is present and may cause cyclic pelvic pain due to obstructed menstrual flow. The ultrasound findings in this case (absence of the uterus) make this diagnosis unlikely.