String-of-Pearls Sign: Ultrasound pattern in PCOS of multiple 2–9 mm peripheral follicles arranged around the ovarian stroma, resembling a string of pearls.
The string-of-pearls sign is a sonographic pattern in polycystic ovary syndrome (PCOS) where multiple small follicles (2–9 mm) are arranged peripherally in the ovary, resembling a necklace of pearls. It reflects arrested follicular development under the influence of elevated androgen levels and is one of the major ultrasound criteria for PCOS diagnosis under Rotterdam and ESMRE guidelines.