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19 Cards in this Set
- Front
- Back
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From which embryological layer are the breasts derived? |
Derived from 2 thickenings of the epidermal ectoderm: the primitive mammary ridge |
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Describe the growth of the mammary ridges in the embryonic period of development |
Mammary ridges appear at week 4 and extend from the axillae to the groin By week 5 they have regressed to the level of the 4th intercostal space Around weeks 5-6, the remnant of the mammary ridge proliferates to give mammary buds |
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How do buds develop to give the breast structure? |
The mammary buds penetrate the underlying mesenchyme, which has an inductive influence on the primary mammary buds The primary buds give rise to secondary buds, which then develop into lactiferous ducts and their branches. These ducts are canalised by the time of birth. The lactiferous ducts form the small ducts and alveoli Only the main ducts are found at birth, and the gland remains undeveloped until puberty |
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Which other tissues contribute to the ectodermal component of the breast? |
Fibrous connective tissue and fat of the mammary gland develop from the surrounding mesenchyme. The mesenchyme also has an inductive effect on the primitive breast bud in the early stages of breast development. It also proliferates under the areola to form the nipple. |
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Describe the development of the nipple |
During the late foetal period, the epidermis becomes depressed to form a shallow mammary pit onto which the ducts open. The nipple itself forms during the perinatal period due to proliferation of the mesenchyme under the areola. |
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What are the main changes seen in the breast in pregnancy? |
- Size and number of lobules increase - Epithelial cells enlarge - Stroma becomes more vascular with aggregates of inflammatory cells |
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What are the main changes seen in the breast in puberty? |
- Increase in fibrous and fatty tissue in the stroma - Followed by ductal changes: ductal elongation and branching under the influence of oestrogen |
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Define terminal ductal lobular unit |
A collection of acini arising from one terminal duct, along with the surrounding intralobular stroma |
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Tell me about the anatomy of the breast lobules |
The lobules are the secretory units of the breast - Each lobule consists of a variable number of acini, embedded in loose connective tissue and connecting to the intralobular duct |
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Tell me about the acini |
Each acini is composed of epithelial and myoepithelial cells - Epithelial cells synthesise milk - Myoepithelial cells are contractile and eject milk into the ducts |
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Outline the sequence of structures of the breast, from external to internal |
Extralobular ducts > subsegmental ducts > segmental ducts > lactiferous ducts and sinuses |
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What are the 2 types of calcification that can be identified on a mammogram? |
1. MACROCALCIFICATION: large white dots or dashes. These are almost always non-cancerous, and require no further testing or follow up 2. MICROCALCIFICATION: fine white specks, like grains of salt. These are usually non-cancerous, but tight clusters with irregular shapes may indicate cause for concern. |
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What are some benign causes of breast calcification? |
- Fibroadenoma - Breast cysts - Fat necrosis - Dermal or vascular calcification - Mammary duct ectasia - Previous radiation therapy for cancer |
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What are 2 main ways of presentation with breast pathology? |
1. Screening: 50-70yrs, 2 view mammography every 3 years. If xray positive, recall for needle biopsy/open biopsy 2. Symptomatic: typically breast lump, breast pain, nipple discharge and skin discharges |
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Outline triple assessment |
1. Clinical history and examination 2. Imaging: ----Mammography: used for palpable and impalpable lesions, looking for deformities or calcification ----Ultrasound: better for younger patients with denser breast tissue for defining the edge of lesions e.g. cysts. 3. Needle biopsy - FNA or core biopsy |
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Outline the procedure of fine needle aspiration cytology |
A needle is inserted into the area with the abnormality, guided by imaging if necessary - Cells are aspirated, stained and examined by pathologists, allowing a rapid diagnosis - There is a risk of false negatives and positives, and no surrounding architecture is seen so not clear if invasive or in situ |
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Describe FNA classification |
C1: insufficient C2: benign C3: atypical, probably benign C4: atypical, probably malignant C5: malignant |
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Outline the procedure of core biopsy |
A core of tissue is removed using a biopsy needle under local anaesthetic, aided by imaging. - This takes longer to process than FNA and is more traumatic - Differentiates in situ vs invasive, giving a tissue diagnosis with architecture - Accurate planning of definitive surgery - Fewer false positives and negatives |
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Describe core biopsy classification |
B1: normal or insufficient for diagnosis B2: benign B3: atypical probably benign B4: atypical probably malignant B5: a/b malignant |
