Breast Flashcards
In terms of pathology, where do most of the breast diseases arise?
The terminal duct lobular unit (TDLU)
The entire ductal-lobular system of the breast is lined by two cell types, what are they?
The inner epithelial cells and outer myoepithelial cells
Why are the myoepithelial cells important in pathology?
Normal function of myoepithelial cells = to contract and propel the secretion forwards, but in pathology it is used as a surrogate marker of differentiating between in-situ and invasive disease. Remember that it is invasive disease once it has invaded the basement membrane, however this can be difficult because invasive tumours can produce their own basement membrane after invasion, so if you stain them for basement membrane material (collagen and laminin), you might be able to find it, so we stain the cells for myoepithelial markers.
What do the markers mean?
If there is in-situ disease, there will not only still be a basement membrane, but the myoepithelial cell layer as well. But if it is an invasive tumour, to invade the basement membrane they have to destroy the myoepithelial cells too.
Name some commonly used markers for myoepithelial cells
Cytokeratin ck5/6, p63 and smooth muscle myosin (SMM)
Give examples of inflammatory diseases of the breast
Acute mastitis
Chronic mastitis
Mammary duct ectasia
Fat necrosis
Tell me about acute mastitis
Usually occurs during the lactation period if the nipple is not looked after very well, because it develops some cracks, allowing bacteria to gain access to the breast, causing it to become acutely inflamed. Advise to breastfeed 8-12 times per day to allow effective milk removal. You can treat with antibiotics if severe. Complications include abscess formation and chronic mastitis.
And chronic mastitis…? What are the two types?
There are two specific types of chronic mastitis. Clinically are not very common but may mimic cancer. 1. Chronic lymphocytic lobulitis. 2. Idiopathic granulomatous mastitis
Tell me about chronic lymphocytic lobultiis
You can see lymphocytes infiltrated within the lobule and the stroma is densely fibrotic. Clinically, produces a very hard lump like a cancer, and can look like a cancer on a radiograph, so we confirm the diagnosis through biopsy, looking for the features described above. Clues in the history: often a history of diabetes, patient >40 yrs
Tell me about idiopathic granulomatous mastitis
Called granulomatous because granulation tissue formation (which is a collection of modified macrophages). We don’t know the cause. ? Some kind of immune response to the antigens in the breast, producing a granuloma. After excluding other causes of granulomas e.g. infective aetiology, when you label as ‘idiopathic granulomatous mastitis’, they need to be treated conservatively. If you perform surgery, you will cause it to further flare up and may end up having to do mastectomy.
What is fat necrosis of the breast?
Can occur because of trauma or because of rupture of a cyst. Clinically can look like cancer because it produces a hard mass. Whenever there is a fat necrosis there will be suppurative dystrophic calcification. One of the features we look for radiologically in cancer is calcification and density, and lesions of fat necrosis produce both calcification and density. However, when you take a biopsy and look under a microscope, you can prove there are macrophages etc, and that it is indeed fat necrosis.
What is mammary duct ectasia?
Duct ectasia means dilatation of the duct. This usually produces periductal inflammation and because of the inflammation, patients can sometimes get a bloody nipple discharge. But bloody nipple discharge is another potential feature of breast cancer. Investigations may include a nipple smear, or biopsy of the area
In terms of proliferative disease, what is a radial scar?
A scar is a dense fibrous tissue that occurs at the end of healing. Radial scars are not related to trauma, but mostly a condition called sclerosing adenosis. It is ‘radial’ because the fibrous tissue pokes out in spikes. This produces a soft tissue density with irregular borders and can hence mimic malignant neoplasm. Even though it is benign, in <1% of cases it is associated with malignancy- so they need to be excised.
Tell me about fibrocystic change
It is a proliferative change of the breast that is age-related and not technically a disease. It is common in 25-45 year olds. Occurs due to the hormonal cycling of oestrogen and progesterone. Cysts slowly grow each cycle under the influence of these hormones. These cysts can cause inflammation and calcium deposition (so can look like cancer on mammography).
What is the difference between hyperplasia and neoplasia?
Both are proliferation of cells, but hyperplasia is when growth is under physiological control, whereas neoplasia is when the cells proliferate without physiological control.
What is the difference between adenoma and papilloma?
Both are benign epithelial tumours. Adenomas form gland structures, whereas papillomas form finger-like structures.
What is the difference between carcinoma and sarcoma?
Both are malignant. Carcinoma is a malignant tumour of epithelial differentiation, and sarcoma is a malignant tumour of mesenchymal differentiation (bone, cartilage, connective tissue etc).
Name some benign neoplastic diseases of the breast
Adenoma
Fibroadenoma
Papilloma
Which is the most common benign tumour of the breast?
Fibroadenoma
Tell me about fibroadenomas
A fibroadenoma is when the benign tumour has both glandular and fibroblastic proliferative changes (so it’s a mixed tumour with both epithelial and mesenchymal differentiation i.e. composed of both proliferating ducts and connective tissue stroma). Often occurs between the ages of 20-35. Get bigger in size in pregnancy but become small and fibrotic after menopause so no need to excise them. No malignant potential. Microscopically, (like any benign tumour), there is a circumscribed border, and in the case of fibroadenoma you will see proliferation of both epithelial and mesenchymal elements.
Name some malignant neoplastic diseases of the breast
Carcinoma
Sarcoma
Paget’s disease
Phylloides tumour
What signs and symptoms might you find regarding a breast lump and what would they make you think about?
Diffuse- fibrosis, fibrocystic change
Discrete- neoplasm, cyst, abscess, hamartoma
Mobile- benign neoplasm
Tethered- Carcinoma