Management of Subcapsular Splenic Cysts (15 mm)
For two subtle subcapsular splenic cysts measuring 15 mm, observation with imaging surveillance is the appropriate management strategy, as asymptomatic splenic cysts demonstrate negative overall growth rates and intervention is reserved only for symptomatic lesions or documented complications.
Initial Assessment and Risk Stratification
The key determinant for management is symptom status, not cyst size 1. The traditional 5 cm threshold for intervention is not firmly supported by evidence, as asymptomatic cysts demonstrate safe natural history regardless of size 1.
Clinical Evaluation Points:
- Assess for symptoms: Left upper quadrant pain, early satiety, or palpable mass 2
- Rule out complications: Rupture risk, intracystic hemorrhage, or infection 2
- Exclude parasitic etiology: Travel history and serologic testing if endemic exposure 3
Recommended Management Algorithm
For Asymptomatic Cysts (15 mm):
Observation is the gold standard 1. The evidence demonstrates:
- Negative overall growth rate in asymptomatic lesions 1
- Safe long-term outcomes with surveillance alone 1
- No size-based threshold mandating intervention 1
Surveillance Protocol:
- Initial imaging: Ultrasound or CT at 6-12 months to establish stability 1
- Long-term follow-up: Annual imaging if stable, extending intervals if no growth 1
- MRI consideration: For better characterization if diagnostic uncertainty exists 4
When Intervention Becomes Necessary
Absolute Indications for Surgery:
- Symptomatic cysts causing pain or mass effect 2, 3
- Complications: Rupture, hemorrhage, or infection 2, 3
- Diagnostic uncertainty: Cannot exclude malignancy 5
- Progressive enlargement with rupture risk (typically >5 cm with symptoms) 3
Surgical Options (If Required):
- Laparoscopic approach preferred for minimally invasive management 5
- Spleen-preserving techniques: Partial cystectomy or enucleation when feasible 2, 3
- Total splenectomy: Reserved for cases where preservation impossible 6
Critical Pitfalls to Avoid
Do not perform percutaneous aspiration as a therapeutic intervention—this has high recurrence rates and should only be used for diagnostic purposes or in non-surgical candidates 1.
Do not recommend surgery based on size alone for asymptomatic lesions, as the 5 cm threshold is not evidence-based for intervention 1.
If splenectomy is performed, mandatory post-operative protocols include 7, 6:
- Pneumococcal, meningococcal, and Haemophilus influenzae type B vaccination
- Lifelong antibiotic prophylaxis (phenoxymethylpenicillin 250-500 mg twice daily)
- Patient education about overwhelming post-splenectomy infection (OPSI) risk
Special Considerations
Subcapsular location (as in this case) does not alter management unless there is concern for imminent rupture or hemorrhage 2. The 15 mm size is well below typical intervention thresholds and poses minimal rupture risk in the absence of trauma 2, 3.
Multiple cysts (two in this case) do not change the observation strategy unless they are complex, multilocular, or symptomatic 6.