Table 1.

Classification of benign breast lesions according to histological origin.

Terminal and lobular ducts

a. Acinar distension

i. Cyst

b. Intralobular connective tissue proliferation

i. Sclerosing adenosis

ii. Fibroadenoma

iii. Phyllodes tumor

iv. Hamartoma

c. Epitelial changes in terminal duct lobular units (TDLUs)

i. Apocrine metaplasia

ii. Ductal and lobular hyperplasia, usual and atypical

iii. Papillomatosis

iv. Intracystic papilloma

Ductal system

d. Ductal ectasia

e. Intraductal papilloma

Lesions of different origin

f. Fatty tissue lesions

i. Lipoma

ii. Liponecrosis

g. Fibrous tissue lesions

i. Focal fibrosis

ii. Diabetic mastopathy

iii. Pseudoangiomatous stromal hyperplasia (PASH)

iv. Myofibroblastoma

h. Vascular origin

i. Hemangioma

i. Inflammatory origin

i. Mastitis/abscess

ii. Tuberculosis and sarcoidosis

iii. Foreign body granuloma and siliconoma

j. Lymph node origin

i. Intramammary lymph nodes