What is the treatment for a large simple cyst?

Treatment of Large Simple Cysts

Simple cysts generally require no treatment and can be followed with routine screening, as they are considered benign with virtually no risk of malignancy. 1

Classification of Cysts

Simple cysts are characterized by specific imaging features:

• Anechoic (cystic)
• Well-circumscribed
• Round or oval shape
• Imperceptible wall
• Posterior enhancement 1, 2

This distinguishes them from:

• Complicated cysts: Contain low-level echoes or intracystic debris without solid components (<2% malignancy risk)
• Complex cysts: Have discrete solid components, thick walls, septations, or intracystic masses (14-23% malignancy risk) 1, 2

Management Algorithm for Large Simple Cysts

Breast Cysts

1. Asymptomatic simple cysts: No further intervention required regardless of size; return to routine screening 1, 2

2. Symptomatic simple cysts: Therapeutic fluid aspiration for symptom relief

   • If fluid is clear: Return to routine screening after resolution
   • If fluid is bloody: Send for cytologic examination 2

Ovarian/Adnexal Cysts

1. Premenopausal women:

   • Simple cysts ≤5 cm: No additional management required
   • Simple cysts >5 cm but <10 cm: Follow-up in 8-12 weeks (ideally during proliferative phase)
   • If cyst persists or enlarges: Refer to gynecologist 1

2. Postmenopausal women:

   • Simple cysts ≤3 cm: No further management required
   • Simple cysts >3 cm but <10 cm: Follow-up at 1 year, then annual follow-up for up to 5 years if stable
   • If cyst enlarges: Refer to gynecologist 1

Follow-up Recommendations

• If a cyst decreases in size by at least 10-15% at any follow-up, no further monitoring is necessary 3
• Stable simple cysts at initial follow-up may benefit from a 2-year follow-up due to measurement variability that could mask growth 3
• Growing simple cysts are likely cystadenomas (benign tumors) 3

Important Considerations

• Ultrasound is the first-line imaging modality for evaluating cysts 2
• The negative predictive value of negative imaging is high (>96%), reinforcing the importance of quality imaging 1, 2
• Biopsy is only recommended if:
  • Aspirated fluid is bloody
  • No fluid can be aspirated
  • A residual mass persists after aspiration
  • A cyst increases in size during follow-up or develops suspicious features 2

Potential Complications

While rare, be aware of potential complications with large simple cysts:

• Hemorrhagic rupture (particularly in patients on anticoagulants) 4
• Misdiagnosis of other cystic entities (e.g., hydatid cysts) that require different management 5

These updated recommendations apply to asymptomatic patients and those whose symptoms are not clearly attributable to the cyst. They provide reassurance regarding the benign nature of simple cysts while minimizing unnecessary follow-up, patient anxiety, and surgical interventions for benign lesions.