A benign cyst that responds to hormonal stimulation and is larger than 3 cm is known as what?

• A. Functional cyst
• B. Dermoid cyst
• C. Hemorrhagic cyst
• D. Paraovarian cyst

Answer: (A)

Functional cysts are benign ovarian cysts that arise from normal ovarian function and respond to hormonal signals. They form when a follicle does not ovulate or when the corpus luteum persists, both driven by hormones, and they typically resolve as the cycle progresses. They can be larger than 3 cm and still represent a normal, self-limited process. On ultrasound, functional cysts are usually simple, thin-walled, unilocular, and anechoic with posterior acoustic enhancement, showing no solid components. Other cysts have different origins and appearances: dermoid cysts often contain mixed echogenic material and calcifications, hemorrhagic cysts display internal echoes with a reticular pattern from blood, and paraovarian cysts arise from the broad ligament and lie separate from the ovary. Therefore, a benign, hormonally responsive cyst larger than 3 cm fits the description of a functional cyst.