What should I do after a breast sonogram showed 15 grape-sized fluid cysts in each breast, with results indicating they are probably benign and my gynecologist (GYN) recommended a 6-month follow-up?

Management of "Probably Benign" Breast Cysts

Your gynecologist's recommendation for 6-month follow-up is appropriate, and your primary care physician's lack of concern is justified—multiple simple or complicated fluid-filled breast cysts with a BI-RADS 3 ("probably benign") assessment carry less than 2% risk of malignancy and require surveillance rather than immediate intervention. 1

Understanding Your Results

What "Probably Benign" (BI-RADS 3) Means

• BI-RADS category 3 findings have a malignancy risk of less than 2%, which is why observation rather than biopsy is the standard approach 1
• Your multiple fluid-filled cysts are most likely either simple cysts (completely benign) or complicated cysts (still very low risk) 1

Types of Breast Cysts

Your cysts are classified based on ultrasound characteristics 1:

• Simple cysts: Completely fluid-filled, well-defined borders, no solid components—these are benign (BI-RADS 2) and require only routine screening 1
• Complicated cysts: Mostly fluid-filled but may contain low-level internal echoes or debris, without solid components—these carry <2% malignancy risk (BI-RADS 3) 1
• Complex cysts: Contain both fluid AND solid components—these have higher malignancy risk (14-23%) and require biopsy 1

What You Should Do

Follow the 6-Month Surveillance Plan

Attend your 6-month follow-up appointment with physical examination and ultrasound (with or without mammography) to assess for any changes in size or characteristics 1:

• Follow-up intervals may range from 6 to 12 months for 1 to 2 years total depending on the radiologist's level of concern 1
• If your cysts remain stable or decrease in size, you can return to routine screening after the surveillance period 1
• If cysts increase in size or develop suspicious features, biopsy would then be indicated 1

Alternative Management Option

Aspiration of the cysts is an acceptable alternative to surveillance, particularly if you are concerned about compliance with follow-up appointments 1:

• This involves draining the fluid with a needle under ultrasound guidance 1
• Cytologic examination is only needed if the aspirated fluid is bloody 1
• However, most clinicians reserve aspiration for symptomatic cysts causing discomfort 1

Important Caveats

When to Seek Earlier Evaluation

Return for evaluation before your scheduled 6-month appointment if you notice 1:

• Rapid increase in breast mass size
• Development of a new palpable lump in a different location
• Skin changes (dimpling, redness, thickening)
• Spontaneous nipple discharge (especially if bloody or from a single duct)

Why Biopsy Is Not Recommended Now

• The negative predictive value of benign imaging findings exceeds 96%, meaning your current assessment is highly reliable 1
• Biopsying all BI-RADS 3 lesions would result in unnecessary procedures for findings that prove benign in over 98% of cases 1
• Exceptions where immediate biopsy might be considered: strong family history of breast cancer, high patient anxiety preventing compliance with follow-up, or if you are unlikely to return for surveillance 1

Compliance Is Critical

• Studies show that many patients with BI-RADS 3 findings are lost to follow-up, which is why some clinicians have a lower threshold for biopsy 1
• Set calendar reminders now for your 6-month appointment to ensure you don't miss this important surveillance

Bottom Line

Your physicians are following evidence-based guidelines correctly. The "probably benign" designation means your cysts are almost certainly not cancer, but the small residual risk requires short-term monitoring to confirm stability. Complete the recommended 1-2 year surveillance period, and if everything remains stable, you can resume normal screening intervals. 1