Ovaries Not Seen on Ultrasound or Surgery: Causes from Agenesis to Adhesions

Failure to visualize ovaries on ultrasound and at exploratory surgery has several explanations, ranging from technical to anatomical.

1. Technical / Imaging Limitations

• Small/prepubertal ovaries: <1 cm³, difficult to resolve transabdominally; transvaginal/transrectal better.
• Obscuring structures: Uterine fibroids, bowel gas, adipose tissue, bladder filling.
• Operator experience/equipment: Low-frequency probes, limited views.

2. Anatomical Variants & Pathology

• Ovarian cysts: Large cysts may displace/replace normal ovarian tissue.
• Adhesions: Prior surgery (cesarean, appendectomy, endometriosis) fixes ovaries to pelvic sidewall, bowel, or uterus—retracted, hidden, or encapsulated.
• Ectopic ovaries: Congenital malposition (e.g., near kidney, inguinal canal) – rare.

3. Congenital Absence

• Unilateral ovarian agenesis: ~1:5,000–1:30,000; often with ipsilateral renal/uterine anomalies (Mayer-Rokitansky-Küster-Hauser spectrum).
• Bilateral agenesis (gonadal dysgenesis): Streak gonads; 46,XY (Swyer) or 46,XX. Presents as primary amenorrhea.

4. Surgical History

• Prior oophorectomy: May be forgotten or undisclosed.
• Hysterectomy with BSO: Ovaries removed.
• Ovarian transposition: Moved pre-radiation.

Diagnostic Approach

1. Repeat transvaginal ultrasound by experienced sonographer
2. Pelvic MRI for soft-tissue detail
3. Hormonal panel (FSH, LH, AMH, estradiol)
4. Karyotype if gonadal dysgenesis suspected
5. Diagnostic laparoscopy (gold standard for visualization)

Absence of ovaries on imaging ≠ absence in body. Systematic evaluation is key.