Benign Epithelial Lesions
Fibrocystic disease of breast
- Fibrocystic change of the breast is one of the most common features seen in the female breast. It is most likely associated with an endocrine imbalance that causes an abnormality of the normal monthly cyclic events within the breast.
- These fibrocystic changes are subdivided into nonproliferative and proliferative changes.
- Nonproliferative changes include fibrosis of the stroma and cystic dilation of the terminal ducts, which, when large may form blue-domed cysts.
- A common feature of the ducts in nonproliferative changes is apocrine metaplasia, which refers to epithelial cells with abundant eosinophilic cytoplasm with apical snouts.
- Proliferative changes include epithelial hyperplasia of the ducts.
- This hyperplastic epithelium may form papillary structures (papillomatosis when pronounced) or may be quite abnormal (atypical hyperplasia).
- Two benign, but clinically important, forms of proliferative fibrocystic change include sclerosing adenosis and radial scar. Both of these maybe mistaken histologically for infiltrating ductal carcinoma, but the presence of myoepithelial cells is a helpful sign that points to the benign nature of the proliferation.
- Sclerosing adenosis is a disease of the terminal lobules that is typically seen in patients 35 to 45 years old. It produces a firm mass, most often located in the upper outer quadrant.
- Microscopically, there is florid proliferation of small ductal structures in a fibrous stroma, which on low power is stellate in appearance and somewhat maintains the normal lobular architecture.
- A radial scar refers to ductal proliferation around a central fibrotic area.
Unlike the situation in other glandular tissues, the commonest type of benign tumour of the breast is a combined product of both connective tissue and epithelial cells; purely epithelial tumours are less frequent.
The benign breast tumours comprise:
- Duct papillomas
- Connective tissue tumours.
A. Fibroadenoma Q
- Commonest type of benign tumour, mainly in young women
- Arises from connective tissue and epithelium
- Clinically, mobile on palpation
- Fibroadenomas are the commonest type of benign tumour of the breast, and are the commonest primary tumour in younger age groups. Q
- Fibroadenomas arise from the breast lobule, from both the loose connective tissue stroma and the glands. Q
- As they are mixed tumours, fibroadenomas will undergo some of the same hormonally induced changes as the surrounding breast.
- Thus, during pregnancy the glands will show lactational changes, and in older women the stroma will become more dense and fibrous.
- During pregnancy, fibroade nomas may grow rapidly in size, but this is due to hormonal affects and is not a sign of malignancy.
B. Histology Q
- Fibroadenomas show duct-like structures or elongated and thinned ductular structures associated with overgrown connective tissue masses.
- Fibroadenoma does not progress to malignancy, although very occasionally a tumour, such as lobular carcinoma, will involve a fibroadenoma.