IS Case 432: Simple breast cyst in a lactating patient

Sara Ann Majewski, MD

University of Rochester

Imaging Sciences URMC 2010
Publication Date: 2010-08-27


A 39-year-old, breast-feeding female presented with a 4–5 mm palpable lump in the lateral right breast along the areolar margin for the past week.


Ultrasound demonstrated a circumscribed, round or oval anechoic structure with imperceptible wall and posterior acoustic enhancement. Mammography demonstrated a circumscribed mass with hypo- or isodense to the parenchyma and possible obscured margin secondary to surrounding tissue.


Simple breast cyst in a lactating patient


Cysts can occur throughout the breasts. They may be secondary to obstructed ducts, enlarge with estrogen exposure and fluctuate during the menstrual cycle. Cysts are line by epithelium and are fluid-filled. They range from microscopic size, up to several centimeters.

Ultrasound (US) is the best modality for cyst diagnosis as cysts cannot be differentiated from solid masses by mammography. In patients under 30 years old with a palpable breast mass, US should be utilized first. In older patients, mammography is obtained first, with ultrasound as indicated. For ultrasound, a high frequency transducer of 10 MHz or greater should be used first. If the lesion is deep, a lower frequency transducer may be utilized.

Differential diagnosis of simple breast cyst includes complicated cyst, carcinoma, diseased lymph node, fat necrosis and post-surgical seroma.

Ultrasound-guided aspiration can be used in problem cases or if symptomatic. A 16 to 22 gauge needle may be utilized depending on fluid viscosity.


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