Non-Inflammatory Benign Breast Lesions

• grossly: FCD often produces palpable breast mass
• pathogenesis FCD results from response of the breast to cyclic changes in levels of estrogens and progesterone- it is unusual before 20 years of age, most commonly seen between ages of 25 to 40 years
• histologically -there are two dominant morphologic patterns:

1. Nonproliferative change

• cyst formation and fibrosis without epithelial hyperplasia- simple fibrocystic disease- most common, is not associated with higher risk of cancer
• the changes consist of increased synthesis of collagen, increased amount of fibrous connective tissue compressing the acini and ducts
• grossly: there are large cysts, the content of the cyst may undergo calcification- visible on mammograph
• histologically: lined by flattened epithelium, occasionally, mild epithelial proliferation-papillae, apocrine metaplasia

2. Proliferative change

• FCD with epithelial cell hyperplasia- proliferative fibrocystic disease
• there is combination of cyst formation and papillary proliferation of the ductal or lobular epithelium
• there may be dysplasia in the epithelium- atypical hyperplasia- these types of FCD are associated with 4-5fold increased risk of cancer

• changes not associated with an increased risk of breast carcinoma:

• fibrosis- and increase in stromal fibrous tissue- ill defined masses-rubbery in consistency
• cyst formation- cysts occur very commonly in FCD- lined by flattened or apocrine epithelium
• inflammation-chronic reaction of lymphocytes and plasma cells or granulomatous foci may be found

• changes associated with increased risk of carcinoma

• usual ductal and lobular hyperplasia without atypia (1.5-2x)
• atypical ductal and lobular hyperplasia (5x):
• marked proliferation of ductal and and lobular epithelium with cytologic atypia
• clinically : patients with fibrocystic disease present with pain, nipple discharge and palpable mass in the breast-necessary to rule out carcinoma- biopsy, occasionally- these lesion produce microcalcification on mammography

• family history of carcinoma- increases risk of cancer in all categories of proliferative lesions (more than 10x)
• hormone replacement therapy

Sclerosing adenosis

• grossly: hard in consistency, resembles carcinoma
• is characterized by increased fibroblast activity and collagen production in the involved lobules.- mammary ducts are compressed, distorted, microscopically close resemblance to ductal invasive carcinoma- basement membrane of ducts is intact, and ducts remain bilayered (outer myoepithelial cell layer)
• the lesion is benign, only minimally increased risk of cancer

Category: Pathology Notes