- 20% of all cancers in women
- Commonest cause of death in women in 35-55 age group
The risk factors identified to date are:
- Female sex; risk increases with age
- Long interval between menarche and menopause
- Older age at first full-term pregnancy
- Obesity and high-fat diet
- Family history of breast cancer
- geographic factors
- Atypical hyperplasia in previous breast biopsy
- Overexposure to oestrogens and
- No definite relationship to oral contraceptives
- Some tumours contain receptors for hormones and respond to hormone manipulation
- No good evidence for viral involvement
- Tumour is confined to ducts (ductal carcinoma in situ) or acini (lobular carcinoma in situ)
- Ductal carcinoma in situ is unilateral, in pre- and post-menopausal women, has several forms and can become invasive Q
- Lobular carcinoma in situ occurs in pre-menopausal women, has no clinical features, is often bilateral, can be multifocal and is a risk marker
There are two forms of non-invasive carcinoma:Q
- Ductal carcinoma in situ
- Lobular carcinoma in situ.
Ductal carcinoma in situ
- Ductal carcinoma in situ can occur in both pre- and post-menopausal women, usually in the 40-60-year age group.
- It can present as a palpable mass, especially if extensive and associated with fibrosis.
- If the larger ducts are involved, presentation can be as a nipple discharge, or as Paget's disease of the nipple. Q
- The disease can be found incidentally in surgical biopsies or be detected by mammography screening, due to the presence of calcification.
- Pure ductal carcinoma in situ accounts for about 5% of breast carcinomas which present clinically. Q
- Histologically, the changes are to be found in the small and medium-sized ducts, although, in older women, the larger ducts can be involved.
- The ducts contain cells which show cytoplasmic and nuclear pleomorphism to varying degrees.
- Mitotic figures may be frequent and can be abnormal.
Lobular carcinoma in situ
- Lobular carcinoma in situ occurs predominantly in pre-menopausal women.
- If it is found after the menopause it is usually associated with an infiltrating tumour.
- A major problem is that it does not present as a palpable lump and is usually found in biopsies removed for other reasons.
- A further important clinical feature is that it is often multifocal within the one breast and is frequently bilateral. Q
- Not surprisingly, there are no specific radiological or macroscopic features.Q
- Histologically, the changes are found in the acini-hence the term, 'lobular'-although they may extend into extralobular ducts and replace ductal epithelium .
- The acini, the normal cells are replaced by relatively uniform cells with clear cytoplasm that appear loose and non-cohesive.
- The overall size of the acini increases, but the lobular shape is retained.
- Unlike the situation in ductal carcinoma in situ, necrosis is unusual.
- Occur in pre- and post-menopausal women
- Most are infiltrating ductal of no special type
- Infiltrating lobular carcinomas can be multifocal
- Less common types include mucinous, medullary, papillary and tubular carcinomas.
The histological types of invasive carcinoma and their relative incidence for palpable tumours are:
- Infiltrating ductal of no special type (75%)
- Mucinous (3%)
- Medullary (3%)
- Others (5%).
- Infiltrating lobular (10%)
- Tubular (2%)
- Papillary (2%)
The macroscopic appearance of the tumours tends to depend on the amount or type of stroma within the carcinoma.
It is this which gave rise to the terms previously applied to tumours: scirrhous, medullary (or encephaloid) and mucinous (or colloid).
Infiltrating ductal carcinomas
- Infiltrating duct or ductal carcinomas of no special type comprise the majority (up to 75%) of infiltrating breast carcinomas.
- Macroscopically, they usually have a scirrhous consistency.
- The size of the tumours varies between patients.
- They can occur in both pre- and post-menopausal women.
- The tumour cells are arranged in groups, cords and gland-like structures.
- Quite marked variations can be seen between different carcinomas even though they are of the same type.
- For example, the size of the solid groups of cells can be variable, and ductal carcinoma in situ is often present.
- The amount of stroma between the tumour cells can also vary, but in those carcinomas in which it is prominent
- It is most marked at the centre, with the periphery being more cellullar.
Infiltrating lobular carcinomas Q
While lobular carcinoma in situ usually occurs in pre-menopausal women, the infiltrating lesion can also occur in post-menopausal women.
Infiltrating lobular carcinomas
have abundant fibrous stroma, so that macroscopically they are always scirrhous.
- While infiltrating ductal carcinomas usually form at one focus in the breast, infiltrating lobular carcinomas can be multifocal throughout the breast. Q
- Histologically the cells are small and uniform and are dispersed singly, or in columns one cell wide 'Indian files', in a dense stroma. Elastosis can be present. Q
- The cells infiltrate around pre-existing breast ducts and acini, rather than destroying them as occurs with invasive duct carcinomas.
- Mucinous carcinomas (also known as colloid, mucoid and gelatinous carcinomas) usually arise in post-menopausal women and comprise 2-3% of invasive carcinomas.
- Macroscopically, the tumours are well circumscribed and have a soft, grey, gelatinous cut surface.
- They vary in size from 10 to 50 mm in diameter. Since there is no dense stroma and the edges are rounded, these tumours do not cause retraction of the nipple or tethering of the skin.
- These carcinomas comprise small nests and cords of tumour cells, which show little pleomorphism, embedded in large amounts of mucin.
- As the name implies, tubular carcinomas are well-differentiated carcinomas composed of cells arranged as tubules. Q
- They are often small lesions, less than 10 mm in diameter, and are firm, gritty tumours with irregular outlines. Q
- Tubular carcinomas form 1-2% of invasive carcinomas but constitute a higher proportion of screen-detected tumours.
- Histologically, they are composed of well-formed tubular structures, the cells of which show little pleomorphism or mitotic activity.
- The stroma is dense, often with elastosis
- The incidence of medullary carcinomas is difficult to assess because not all the criteria for diagnosis have been strictly adhered to in some studies; hence figures have ranged from very rare to 5%.
- These tumours usually occur in post-menopausal women.
Medullary carcinomas are circumscribed and often large.
- Histologically, they are composed of large tracts of confluent cells with little stroma in between them.
- The cells show quite marked nuclear pleomorphism, and mitotic figures are frequent. There is never evidence of gland formation.
- These cytological appearances put them into the 'poorly-differentiated' category.
- Around the islands of tumour cells there is a prominent lymphocytic infiltrate, predominantly T-lymphocytes, with macrophages. Q
Papillary carcinomas Q are rare tumours which occur in post-menopausal women.
- They are usually circumscribed and can be focally necrotic, with little stromal reaction.
- The tumours are in the form of papillary structures, and areas of intraductal papillary growths are usually found.
Paget's disease of the nipple
- Erosion of the nipple clinically resembling eczema
- Associated with underlying ductal carcinoma in situ or invasive carcinoma
- Clinically, there is roughening, reddening and slight ulceration of the nipple, similar to the skin changes of eczema.
- Recognition is important, as it is associated with an underlying carcinoma, mainly in the subareolar region.
- Paget's disease of the nipple occurs with about 2% of all breast carcinomas, and is associated with a higher frequency of multicentric breast carcinomas.
- Within the epidermis of the nipple, large, pale-staining malignant cells can be seen histologically and these cause the changes seen clinically. The malignant cells are derived from the adjacent breast carcinomas.
Spread of breast carcinomas Q
- Directly into skin and muscle
- Via lymphatics to axillary and other local lymph nodes
- Via blood stream to lungs, bone, liver and brain
- May be considerable delay before metastasis occurs