Breast cyst: Meaning in a Radiology Report

Breast cyst

Also written as: simple breast cyst, complicated cyst, clustered microcysts

A breast cyst is a round sac filled with fluid inside the breast. Simple cysts are benign and very common, especially in the years before menopause.

Seen on: Ultrasound, Mammogram

How it reads in a report

Multiple bilateral simple breast cysts, the largest measuring 11 mm at 2 o'clock in the left breast (BI-RADS 2: benign).

What it means

Breast cysts form when fluid collects in the milk glands, often with normal hormone changes. On a mammogram a cyst looks like a smooth lump, and ultrasound shows that it holds fluid. A simple cyst is black inside on ultrasound (anechoic), with a thin wall and a brighter area behind it. A complicated cyst has some debris inside. A complex cyst has thick walls or solid parts.

When it matters

Simple cysts are benign (BI-RADS 2) and need no extra follow-up. If one is large or painful, it can be drained with a fine needle. Complicated cysts are also usually benign and may be checked with a short-term follow-up ultrasound or drained. A complex cyst with solid parts is different and usually leads to a biopsy. Cysts often change in size with the menstrual cycle and can come and go.

Questions to ask your doctor

Is this a simple cyst, or does it have debris or solid parts?
Does it need follow-up, or can it be left alone?
Could draining it help if it becomes painful?

General information, not medical advice. What a finding means for you depends on your symptoms, your history and the images themselves, so talk your results through with a doctor.