Management of Physiological Breast Cysts
Simple (physiological) breast cysts require no intervention beyond routine screening mammography, as they are essentially benign with no associated malignancy risk. 1, 2
Classification and Risk Assessment
Breast cysts must first be classified by ultrasound characteristics to determine appropriate management 3, 1:
Simple cysts are anechoic (completely fluid-filled), well-circumscribed, round or oval with imperceptible walls and posterior acoustic enhancement—these are BI-RADS 2 (benign) with essentially 0% malignancy risk 1, 2
Complicated cysts contain low-level internal echoes or debris but lack solid components, thick walls, or thick septa—these carry very low malignancy risk (<2%) 3, 1, 2
Complex cysts contain discrete solid components including thick walls (>0.5mm), thick septa, or intracystic masses—these carry significantly higher malignancy risk (14-23%) and require different management 3, 1, 2
Management Algorithm for Simple (Physiological) Cysts
For simple cysts that are concordant with clinical findings, return to routine screening only—no aspiration, no follow-up imaging, no intervention is needed. 1, 2
Optional Aspiration Scenarios
Aspiration may be considered only in specific situations 3, 4:
- Symptomatic patients with pain or discomfort from the cyst 3
- Patients likely to be lost to follow-up 3
- When aspiration is performed, typical clear or yellow-green cyst fluid can be discarded without cytologic examination 4
- Bloody fluid requires cytologic evaluation with tissue marker placement 1, 4
Important Caveats
- Cyst recurrence occurs in approximately 26% of cases after aspiration, particularly in patients with bilateral or multiple cysts 5
- The high recurrence rate after aspiration supports the conservative "no intervention" approach for asymptomatic simple cysts 5
- Ultrasound is the key imaging modality for characterizing breast cysts and should be used to confirm simple cyst features before adopting a surveillance-only approach 3
When Simple Cysts Require Further Action
If a lesion initially classified as a simple cyst develops any of the following features, reclassification and tissue sampling become necessary 5:
- Thick cyst wall development
- Mural tumor or eccentric mass appearance
- Internal septations
- Size >3 cm (associated with 33% cancer risk in one study) 5