What is the diagnosis and management for a 12-year-old female patient with abdominal pain, vomiting, and a history of only one menstrual cycle, who presents with a bulky right ovary replaced by a thick-walled cystic lesion with low-level internal echoes and internal septations on ultrasound (USG), along with mild free fluid in the pouch of Douglas (POD) and multiple prominent subcentimetric mesenteric lymph nodes?

Diagnosis and Management of Hemorrhagic Ovarian Cyst in a 12-Year-Old with Acute Abdomen

This 12-year-old presents with a classic hemorrhagic corpus luteum cyst (O-RADS 2 classification, <1% malignancy risk) that requires conservative management with follow-up ultrasound in 8-12 weeks to confirm spontaneous resolution. 1, 2, 3

Diagnostic Confirmation

The ultrasound findings are pathognomonic for a hemorrhagic ovarian cyst:

• Thick-walled cystic lesion with low-level internal echoes and septations represents the characteristic reticular pattern or retracting clot seen in hemorrhagic cysts 4, 1, 3
• Absence of significant internal vascularity on Doppler is the critical feature distinguishing hemorrhagic content from solid components that would suggest malignancy 1, 2, 3
• The combined sonographic features of internal echoes with peripheral vascularity only are diagnostic of hemorrhagic cyst in 95% of cases 4

Key diagnostic pitfall to avoid: Do not misinterpret the internal septations and echoes as solid components without confirming absence of internal blood flow on color Doppler 1, 3

Risk Stratification

This lesion classifies as O-RADS 2 (Almost Certainly Benign, <1% malignancy risk) based on:

• Classic hemorrhagic features with low-level internal echoes 1, 3
• Absence of internal vascularity (no mural nodules or papillary projections with blood flow) 1, 3
• Smooth wall characteristics despite thickness 3

The septations do not upgrade the classification when other hemorrhagic features are present and vascularity is absent 1

Clinical Context: Primary Amenorrhea Consideration

The history of only one menstrual period 6 months ago raises concern for:

• Anovulatory cycles or oligoovulation, though paradoxically hemorrhagic cysts are uncommon in anovulatory states 5
• This single cycle may have been the ovulatory event that produced this corpus luteum cyst 6, 7
• The 12-year age places her in early menarche where irregular cycles are physiologic, but persistent amenorrhea after 6 months warrants endocrine evaluation after acute management 7

Management Algorithm

Immediate Management (Current Presentation)

Conservative management is appropriate given:

• Hemodynamic stability (no mention of shock or severe hemorrhage) 8
• Mild free fluid in POD suggests contained hemorrhage without active bleeding 8
• Pain and vomiting are consistent with cyst expansion but not rupture requiring surgery 6, 8

Specific interventions:

• Analgesics for pain control 8
• Anti-emetics for symptomatic relief 8
• Monitor hemoglobin levels to exclude ongoing hemorrhage 1
• Avoid invasive procedures during acute phase 2

Follow-Up Imaging Protocol

Schedule repeat transvaginal or transabdominal ultrasound (age-appropriate) in 8-12 weeks to confirm spontaneous resolution 1, 2, 3

• Timing should ideally be during proliferative phase (after menstruation if cycles resume) 3
• Expected outcome: Complete resolution in 3.5 ± 2.4 weeks on average 9
• If cyst persists, enlarges, or develops changing morphology → refer to pediatric gynecology 1, 2

Size-Based Considerations

The cyst size is not explicitly stated, but management differs:

• If ≤5 cm: No further management needed after confirmation of resolution 1, 2
• If >5 cm but <10 cm: Follow-up ultrasound mandatory 1, 2
• If ≥10 cm: Automatically upgrades to O-RADS 3 regardless of benign features, requiring gynecology referral 3

Additional Findings Requiring Attention

Mesenteric Lymph Nodes

Multiple subcentimetric mesenteric lymph nodes are likely reactive given:

• Subcentimetric size (<1 cm) is within normal limits 4
• Common reactive finding with pelvic inflammation or hemorrhage 4
• No specific intervention required unless they enlarge on follow-up

Low-Level Echoes in Bladder

Urine routine examination is mandatory as recommended by the radiologist to exclude:

• Hematuria (from adjacent pelvic pathology or unrelated urinary tract process) 4
• Debris or infection 4

Indications for Surgical Intervention

Laparoscopy would be indicated only if:

• Hemodynamic instability develops (tachycardia, hypotension, dropping hemoglobin) 8
• Acute abdomen with peritoneal signs suggesting rupture with significant hemoperitoneum 6, 8
• Concern for ovarian torsion (though current ultrasound shows normal vascularity, making this unlikely) 4, 8
• Cyst persists or enlarges at 8-12 week follow-up 1, 2

Critical surgical principle: If surgery becomes necessary and malignancy cannot be excluded, ensure pediatric gynecologic oncology consultation before intervention, as appropriate surgical staging is the second most important prognostic factor after stage 3

Prevention of Recurrence

After acute resolution, consider:

• Combined oral contraceptive pills to suppress ovulation and prevent recurrent hemorrhagic cysts 8
• However, defer this decision until menstrual pattern is established and endocrine evaluation completed given the primary amenorrhea history 5, 7

What NOT to Do

• Do not perform fine-needle aspiration of this cyst—it is absolutely contraindicated 1, 2
• Do not operate on functional cysts in stable patients—most resolve spontaneously even when >5 cm 3
• Do not obtain CT or MRI as initial imaging—ultrasound is diagnostic and avoids radiation in this pediatric patient 4
• Do not assume all pelvic pain in adolescents is functional without proper ultrasound characterization 7