Metastases to the breast
Metastases to the breast from non-mammary primary tumors are uncommon and account for 0.5-2.0% of all breast malignancies.
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Clinical presentation
Metastases do not tend to cause retraction of the skin or nipple. Metastatic lesions are much more likely to be multiple or bilateral than primary cancers.
Pathology
Breast metastases from extra-mammary malignancies are unusual, and if present, typically indicate widely disseminated disease. They tend to be found in the subcutaneous fat, whereas primary breast cancers develop in glandular tissue.
Primary sites
The most frequent source of a metastatic breast lesion is the contralateral breast 2. The most common extra-mammary cancers that metastasize to the breast are:
- lymphoma/leukemia: most common extramammary source 2
- melanoma
- sarcomas
- prostate cancer: considered on the most frequent primary sites in men 4
- lung cancer
- gastric cancer
- ovarian cancer
- renal cell cancer
- malignant mesothelioma 5
- carcinoid tumor 6
- carcinoma of the cervix 7
- rectal cancer 8
- papillary thyroid carcinoma 9
Radiographic features
Like other metastasis, metastases to the breast tend to be rounded and well defined. As opposed to breast cancer, calcification is unusual.
Mammography
On mammography, metastatic lesions may manifest as single or multiple masses or as diffuse skin thickening. Metastases usually appear as round masses with circumscribed or ill-defined borders. They typically lack spiculation. Microcalcifications are rare can occur with some primary type (e.g, psammoma bodies in ovarian cancer).
Ultrasound
On ultrasound, metastatic masses tend to have circumscribed margins with low-level internal echoes and, occasionally, posterior acoustic enhancement. Color Doppler interrogation most often shows increased vascularity.
History and etymology
The first case of a metastatic lesion to the breast is thought to have been reported by Trevithick in 1903 4.
Differential diagnosis
On mammography several other primary breast lesions may easily mimic that of a typical well-defined metastasis which may be benign or malignant:
Rarely, metastasis to the breast may be spiculated and mimic an invasive ductal carcinoma.
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Breast imaging and pathology
- breast screening
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mammography
- breast imaging and the technologist
- forbidden (check) areas in mammography
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mammography views
- craniocaudal view
- mediolateral oblique view
- additional (supplementary) views
- true lateral view
- lateromedial oblique view
- late mediolateral view
- step oblique views
- spot view
- double spot compression view
- magnification view
- exaggerated craniocaudal (axillary) view
- cleavage view
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- bullseye CC view
- rolled CC view
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- 20° oblique projection
- inferomedial superolateral oblique projection
- Eklund technique
- normal breast imaging examples
- digital breast tomosynthesis
- breast ultrasound
- breast ductography
- breast MRI
- breast morphology
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- malignant lesions
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breast cancer
- breast adenocarcinoma
- ductal breast carcinoma
- ductal carcinoma in situ (DCIS)
- invasive ductal carcinoma
- lobular breast carcinoma
- ductal breast carcinoma
- adenoid cystic carcinoma of the breast
- apocrine carcinoma of the breast
- breast cancer metastases
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- male breast cancer
- malignant phyllodes tumor
- metastases to the breast
- metaplastic carcinoma the breast
- gamuts
- breast adenocarcinoma
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breast cancer
- borderline breast disease / high risk breast lesion
- benign lesions
- adenosis of the breast
- benign papillary lesions of the breast
- breast cyst
- breast hematoma
- breast hamartoma
- breast lipoma
- ductal adenoma of the breast
- epidermal inclusion cysts of the breast
- fat necrosis of the breast
- fibroadenoma
- granular cell tumor of the breast
- gynecomastia
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- mammary fibromatosis
- oil cyst
- phyllodes tumor
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- post-traumatic fibrosis
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breast calcifications (approach)
- morphology
- distribution
- location
- lobular calcification within breast tissue
- intraductal calcification within breast tissue
- milk of calcium within a breast cyst
- vascular calcification in breast tissue
- skin (dermal) calcification in / around breast tissue
- suture calcification within breast tissue
- stromal calcification within breast tissue
- artifactual calcification from outside the breast
- suspicious breast calcifications
- infection/inflammation
- vascular lesions
- systemic disease
- gamuts
- classification systems
- malignant lesions
- breast cancer staging