Gynecology Topic 28. Functional cysts of ovaries

I. Functional Ovarian Cysts

Definition

• Functional ovarian cysts: Benign cysts arising from normal ovarian follicular activity.
• Typical in reproductive age; most are transient and regress spontaneously.
• Postmenopausal adnexal cyst/mass needs more caution because functional cysts are less expected.

Types

1. Follicular cyst

• Most common functional cyst.
• Pathogenesis: Failure of Graafian follicle rupture → continued follicular growth.
• Lining: Granulosa cells; contents: Clear fluid.
• Size: Usually 3-8 cm; simple follicles <2.5-3 cm are physiological.
• Clinical: Usually asymptomatic; may cause pelvic pain, delayed menses or AUB.
• Course: Usually regresses or ruptures spontaneously within weeks / 2-3 cycles.

2. Corpus luteum cyst

• Pathogenesis: Corpus luteum fails to regress after ovulation and continues progesterone secretion.
• Often hemorrhagic → Contains blood (corpus hemorrhagicum).
• Size: Usually 3-6 cm.
• Clinical: Delayed menstruation, dull unilateral lower abdominal/pelvic pain.
• Rupture/bleeding → Acute pain, hemoperitoneum, peritoneal irritation, shock if severe.

3. Theca lutein cyst

• Pathogenesis: Excessive hCG stimulation → Luteinization and hypertrophy of theca interna cells.
• Usually bilateral, often multilocular, filled with clear/straw-colored fluid.
• Causes: Molar pregnancy, choriocarcinoma, multiple pregnancy, ovulation induction / ovarian hyperstimulation.
• May become very large; increased risk of torsion, rupture, hemorrhage.
• Course: Usually regresses when hCG level falls or the pregnancy/trophoblastic disease resolves.

II. Clinical Features

Symptoms

• Mostly asymptomatic → Incidental finding on pelvic examination or ultrasound.
• Lower abdominal/pelvic pain, heaviness or pressure.
• Menstrual disturbance: Delayed menstruation, irregular bleeding, heavy bleeding.
• Large cyst: Dyspareunia, urinary frequency, constipation, palpable mobile adnexal mass.

Complications

• Ovarian torsion → Sudden severe unilateral pelvic pain, nausea/vomiting; gynecologic emergency.
• Cyst rupture → Sudden pain; hemorrhagic cyst rupture may cause hemoperitoneum and shock.
• Hemorrhage into cyst → Acute pain, falling hemoglobin if severe.
• Peritonitis-like picture may occur after rupture with blood/irritating fluid.

III. Diagnosis

Initial Assessment

• History: Pain onset, menstrual pattern, pregnancy risk, fertility treatment, trophoblastic disease symptoms.
• Physical examination: Abdominal + bimanual pelvic examination → Tender, mobile adnexal mass.
• Reproductive-age patient: Always exclude pregnancy/ectopic pregnancy → urine/serum β-hCG.
• Theca lutein suspicion: Quantitative β-hCG + search for molar pregnancy, choriocarcinoma or ovarian hyperstimulation.

Ultrasound

• Primary diagnostic tool: Pelvic ultrasound, preferably transvaginal ± transabdominal for large masses.
• Typical follicular/simple functional cyst:

• Small/moderate size, usually <8 cm.
• Unilateral, mobile, unilocular, anechoic, thin smooth wall.
• No solid component, papillary projection, thick septation or internal vascularity.

• Corpus luteum cyst: Thick wall, peripheral vascularity, internal echoes if hemorrhagic.
• Theca lutein cysts: Often bilateral, large, multilocular cystic ovarian enlargement.

Laboratory Tests and Differential Diagnosis

• CA-125: Not diagnostic for functional cysts; use mainly if postmenopausal or US is suspicious for malignancy.
• CA-125 is nonspecific in premenopausal women → endometriosis, PID, fibroids, pregnancy and menstruation may elevate it.
• Suspicious US/clinical signs: Solid areas, papillary projections, thick septations, irregular wall, ascites, fixed mass, postmenopause.
• Differential diagnosis: Ectopic pregnancy, ovarian torsion, endometrioma, benign/malignant ovarian neoplasm, PID/tubo-ovarian abscess, appendicitis or urinary pathology.

IV. Treatment

Observation

• Most asymptomatic simple cysts in reproductive-age women → Observation.
• Repeat ultrasound after weeks / next cycles if cyst is larger, uncertain, symptomatic but stable, or not confidently physiological.
• Small simple cyst in a premenopausal asymptomatic patient often needs no treatment if confidently characterized.
• Persistent, enlarging, complex or postmenopausal cyst → Gynecologic evaluation and possible surgery.

Medical Treatment

• Analgesia: NSAIDs if stable and uncomplicated.
• Combined OCPs:

• Suppress ovulation → May prevent new functional cyst formation.
• Do not reliably speed resolution of an existing cyst.

• Theca lutein cysts → Treat/remove the hCG stimulus (molar pregnancy, choriocarcinoma, OHSS); expect regression when hCG decreases.

Surgical Treatment

• Urgent surgery: Ovarian torsion, hemodynamically significant rupture/hemoperitoneum, peritonitis, suspected ectopic pregnancy.
• Elective surgery: Large persistent cyst (>8 cm), increasing size, recurrent symptoms, suspicious US findings, postmenopausal mass requiring removal.
• Preferred in reproductive-age women: Laparoscopic ovarian cystectomy with ovarian preservation if possible.
• Oophorectomy/adnexectomy: Suspicious malignancy, nonviable ovary after torsion, or postmenopausal patients depending on risk.
• Suspected malignancy → Refer to gynecologic oncology; avoid cyst rupture/spillage.