In PCOS, ultrasound may show which characteristic appearance of the ovaries?

• A. Single large ovarian cyst
• B. Normal ovaries
• C. Multiple small follicles around the periphery ("string of pearls")
• D. Absence of ovarian structure

Answer: (C)

Ultrasound findings in PCOS typically show enlarged ovaries with many small follicles arranged around the outer edge, producing a peripheral “string of pearls” appearance. These follicles are usually 2–9 mm in diameter and numerous, reflecting arrested follicular development and the characteristic anovulatory state. The ovary tends to have increased volume as well, due to the combination of numerous small follicles and altered stroma.

This pattern is distinct from a single large ovarian cyst, which points to a solitary follicular or corpus luteum cyst rather than the polycystic pattern. Normal ovaries would not explain the clinical features of PCOS, and absence of ovarian structure would suggest a different condition such as ovarian agenesis or prior surgical removal.