2/2 fluid accumulation in the TDLU bc of distention and obstruction of the efferent ductule.

Can be solitary or multiple.

Can cause sx: palpable mass and/or pain

Can fluctuate in size, number and sx over time.

Influenced by hormonal fluctuations

• Can be seen in pre-, peri-, and postmenopausal women

• Cyclical

Found in 37.5% of all women

• MC in 35-50 yo

BR 2 - benign

• No increased risk of breast CA

Papillary apocrine changes aka apocrine metaplasia are changes that occur 2/2 irritation

Benign morphological change of the TDLU epithelium to secretory epithelium with associated acinar dilatation

• Detected on US as clustered microcysts if they become large enough.

Apocrine-like cells form in a linking of developing microcysts 2/2 increased intraluminal pressure

Common finding in the breast; incidence as high as 85% at autopsy

Associated with fibrocystic changes

Cluster of small cysts (aka microcysts, 2-5 mm) with intervening septae

Aprocrine metaplasia/hyperplasia is a benign diagnosis

BR 2 - benign

RISK

• No associated risk of upgrade to malignancy at excision

• There is an increased risk of developing CA when hyperplasia is seen along with metaplasia 

Tx:

• If imaging is concordant, no further tx is needed.

• When the pathologist finds cytologic or architectural atypia, excision is recommended due to the association with upgrade to apocrine ductal carcinoma in situ or apocrine carcinoma.