What is the role of adenosis and fibroadenoma in the etiology of breast masses?

Updated: Jul 27, 2020
  • Author: Andrew C Miller, MD; Chief Editor: Jeter (Jay) Pritchard Taylor, III, MD  more...
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Answer

An increase in the number of glands.

Fibroadenoma [6, 16, 37]

Fibroadenoma is the most common cause of breast mass in women younger than 35 years and comprises 91% of all solid breast masses in females younger than 19 years. [37] These arise from the terminal duct lobular unit and appear clinically as singular, firm, rubbery, smooth, mobile, painless masses ranging in size from 1-5 cm. They may grow to a large size, thereby affecting the contours of the overlying skin and overall shape of the breast. Ultrasonography reveals a well-defined hypoechoic homogeneous mass 1-20 cm in diameter. [16, 37] Fibroadenomas appear as multiple masses in 10%-15% of patients. [16]

Breast adenoma. A) A breast adenoma is oval with w Breast adenoma. A) A breast adenoma is oval with well-defined borders. It may be hypoechoic and some internal echogenicity may be seen. It is wider than tall and posterior acoustic enhancement is NOT seen, helping distinguish from a cyst or other fluid collection. B) An arrow indicates the adenoma.
Loculated breast abscess, curvilinear. A) This is Loculated breast abscess, curvilinear. A) This is the same abscess seen in the above image and is imaged with a curvilinear transducer to better appreciate the extent of the abscess. It is important to image the abscess completely for width and depth. B) The abscess is outlined in yellow and the ribs and posterior acoustic enhancement are noted.
Purulent breast abscess. A) A purulent breast absc Purulent breast abscess. A) A purulent breast abscess is seen. The fluid is echogenic, but can be recognized as a disruption of the surrounding tissue and posterior acoustic enhancement. B) The abscess is outlined in yellow and the posterior acoustic enhancement is noted.
Complex breast abscess. In this clip, the features of a loculated breast abscess containing echogenic purulent material are noted. Example of imaging with a linear high-frequency transducer.
Loculated breast abscess, curvilinear. In this clip, a large, loculated breast abscess and its features are noted. Example of imaging with a lower-frequency curvilinear transducer to better appreciate the extent of this large abscess.

Phyllodes tumor [6, 37]

Phyllodes tumor is also known as cystosarcoma phyllodes or giant fibroadenoma. Although generally benign, a malignant variant occurs in 10% of cases. Incidence is highest among women aged 40-60 years. Phyllodes tumor is also the most common primary breast malignancy in adolescents. [37] The most common presentation is that of a large (average 5 cm), solitary, firm, breast nodule. Ultrasonographic findings of the mass may appear identical to those of a fibroadenoma with well-circumscribed borders and small cysts. [37]


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