In a reproductive‑age woman with ultrasound showing a left ovary ~10 cc and right ovary ~8.5 cc, both with multiple peripherally arranged follicles and echogenic stromal pattern, and presenting with right iliac fossa tenderness, what is the most likely diagnosis and initial management?

Polycystic Ovary Syndrome (PCOS) with Acute Right Iliac Fossa Tenderness

The ultrasound findings of bilateral ovarian enlargement (left 10cc, right 8.5cc) with multiple peripherally arranged follicles and echogenic stroma are diagnostic of polycystic ovarian morphology (PCOM), and when combined with right iliac fossa tenderness, you must immediately rule out ovarian torsion or hemorrhagic cyst rupture before confirming PCOS diagnosis. 1

Immediate Clinical Assessment Required

The right iliac fossa tenderness is the critical finding that demands urgent evaluation, as this symptom pattern can indicate:

• Ovarian torsion: The enlarged polycystic ovaries (both >8cc) increase torsion risk, presenting with acute pelvic pain and adnexal tenderness 1
• Hemorrhagic cyst rupture: Common in PCOS patients, causing acute pain with peritoneal irritation 1
• Tubo-ovarian abscess: Less likely but must be excluded, especially if fever or leukocytosis present 1

Key Physical Examination Findings to Document

• Perform bimanual and rectovaginal examination to assess for adnexal mass mobility, cervical motion tenderness, and peritoneal signs 1
• Check vital signs for tachycardia or fever suggesting infection or significant hemorrhage 1
• Assess for rebound tenderness, guarding, or rigidity indicating peritoneal irritation 1

Diagnostic Imaging Interpretation

Ultrasound Features Consistent with PCOM

The described findings meet diagnostic criteria for polycystic ovarian morphology:

• Ovarian volumes: Left ovary 10cc and right ovary 8.5cc both fall within the range where PCOM is diagnosed (threshold >10mL has 81% sensitivity and 84% specificity) 1, 2
• Multiple peripherally arranged follicles: This classic "string of pearls" appearance is characteristic of PCOM 1
• Echogenic stroma: Increased stromal echogenicity is a recognized feature of polycystic ovaries, though less commonly used for diagnosis than follicle count or volume 1

Critical Additional Ultrasound Assessment Needed

You must obtain or review the complete ultrasound report to determine:

• Follicle number per ovary (FNPO): Count of 2-9mm follicles, with ≥20 follicles being the gold standard (87.64% sensitivity, 93.74% specificity) or ≥26 follicles using updated criteria (85% sensitivity, 94% specificity) 1, 2
• Presence of dominant follicle or corpus luteum: These must be absent for PCOM diagnosis 3
• Evidence of torsion: Look for twisted vascular pedicle, absent or abnormal ovarian blood flow on Doppler, or deviation of uterus toward affected side 1
• Free fluid in pelvis: Suggests hemorrhagic cyst rupture or other acute pathology 1
• Both ovaries must be evaluated: 23.5% of PCOS patients show PCOM in only one ovary, and examining only one side misses 9.4% of diagnoses 4

Differential Diagnosis Priority

Acute Conditions Requiring Immediate Intervention

1. Ovarian torsion: Enlarged polycystic ovaries predispose to torsion; requires emergency surgical detorsion within 4-8 hours to preserve ovarian function 1
2. Hemorrhagic cyst rupture: Can cause significant hemoperitoneum requiring observation or intervention 1
3. Appendicitis: Right iliac fossa tenderness mandates exclusion of appendiceal pathology 1

Chronic Conditions After Acute Pathology Excluded

1. PCOS: Requires meeting Rotterdam criteria (2 of 3: oligo/anovulation, clinical/biochemical hyperandrogenism, PCOM) after excluding other causes 1, 5, 6
2. Functional ovarian cysts: Can mimic PCOM but typically resolve spontaneously 1

Initial Management Algorithm

Step 1: Urgent Evaluation (Within Hours)

• If severe pain, peritoneal signs, or hemodynamic instability: Obtain immediate surgical consultation for possible ovarian torsion or significant hemorrhage 1
• If moderate pain with stable vitals: Proceed with complete ultrasound assessment including Doppler flow studies 1

Step 2: Complete Diagnostic Workup (Within Days)

Once acute pathology is excluded, confirm PCOS diagnosis using Rotterdam criteria:

Required Clinical Assessment

• Menstrual history: Document cycle frequency over past year; oligomenorrhea defined as cycles >35 days apart or <8 cycles per year 5, 6
• Hyperandrogenism evaluation: Assess for hirsutism (modified Ferriman-Gallwey score ≥4-6), acne, or androgenic alopecia 7, 5

Essential Laboratory Tests

• Total testosterone by LC-MS/MS: 74% sensitivity, 86% specificity; preferred over immunoassays (92% vs 78% specificity) 7
• Free testosterone: 89% sensitivity, 83% specificity; superior to total testosterone alone 7
• TSH: Exclude thyroid dysfunction causing menstrual irregularity 7, 5
• Prolactin (morning fasting): Exclude hyperprolactinemia 7, 5
• 17-hydroxyprogesterone: If DHEAS elevated, screen for non-classical congenital adrenal hyperplasia 7

Metabolic Screening

• 75g oral glucose tolerance test: Screen for glucose intolerance and type 2 diabetes (4x higher risk in PCOS) 7, 5
• Fasting lipid panel: Assess cardiovascular risk 7
• Calculate BMI and waist-hip ratio: WHR >0.9 indicates truncal obesity 7

Step 3: Confirm PCOS Diagnosis

PCOS diagnosis requires 2 of 3 Rotterdam criteria:

1. Oligo/anovulation: Irregular menstrual cycles or mid-luteal progesterone <6 nmol/L 7, 6
2. Clinical or biochemical hyperandrogenism: Hirsutism, acne, alopecia, or elevated androgens 7, 5, 6
3. PCOM on ultrasound: FNPO ≥20 follicles (or ≥26 by updated criteria) and/or ovarian volume >10mL 1, 3, 2

Plus exclusion of other disorders: Thyroid dysfunction, hyperprolactinemia, non-classical CAH, Cushing's syndrome, androgen-secreting tumors 7, 5

Critical Clinical Pitfalls

• Do not diagnose PCOS in adolescents <2 years post-menarche or with gynecological age <8 years: Multifollicular ovaries are physiologic in this population, causing high false-positive rates 7, 3
• Do not rely on ultrasound alone: PCOM is present in 22% of normal women and up to one-third of reproductive-aged women without PCOS 1, 6
• Do not test hormones while on hormonal contraception: Results are unreliable; defer testing until after contraceptive removal 7
• Do not miss androgen-secreting tumors: Rapid symptom onset, severe virilization, or very high testosterone (>150-200 ng/dL) requires immediate imaging for tumor 7, 5
• 30% of PCOS patients have normal testosterone: Clinical hyperandrogenism plus irregular cycles can establish diagnosis even with normal labs 7

Treatment Approach After Diagnosis Confirmation

For Acute Pain Management

• Analgesics: NSAIDs for pain control if no contraindications 1
• Observation: If hemorrhagic cyst rupture with stable hemodynamics, serial hemoglobin monitoring 1
• Surgery: If torsion confirmed or hemodynamic instability from hemorrhage 1

For Long-Term PCOS Management

• Weight loss if overweight: First-line intervention improving all PCOS manifestations 5
• Hormonal contraceptives: First-line for menstrual irregularity and dermatologic symptoms 5
• Metformin: First-line for metabolic manifestations including hyperglycemia 5
• Clomiphene or letrozole: First-line for infertility treatment 5