Pathology Cheat Sheet
Report the Invasive Pattern
Breast carcinoma for NEET-PG: invasive ductal vs lobular E-cadherin, DCIS comedo, ER PR HER2 subtypes, triple-negative BRCA1, Paget disease, and gynaecomastia.
MedNext Academy | 3 min read
Report the Invasive Pattern
Breast carcinoma for NEET-PG: invasive ductal vs lobular E-cadherin, DCIS comedo, ER PR HER2 subtypes, triple-negative BRCA1, Paget disease, and gynaecomastia.
The pathology, molecular classification and staging of breast carcinoma, and the causes of gynaecomastia.
High-yield lines
- Invasive ductal carcinoma of no special type is the most common breast malignancy and often shows a stellate firm mass with desmoplasia.
- Invasive lobular carcinoma shows a single-file infiltration pattern due to loss of E-cadherin.
- Ductal carcinoma in situ is malignant proliferation confined within the ducts, and comedo type shows central necrosis.
- Molecular classification uses oestrogen receptor, progesterone receptor, and HER2 status.
- Luminal tumours are hormone-receptor positive and generally have a better prognosis.
- HER2-positive tumours overexpress the HER2 oncogene and respond to trastuzumab.
- Triple-negative breast cancer lacks ER, PR, and HER2 and is associated with BRCA1 mutation.
- Paget disease of the nipple reflects underlying ductal carcinoma with malignant cells in the epidermis.
- Axillary lymph node status is the single most important prognostic factor in breast cancer.
- BRCA1 and BRCA2 germline mutations markedly increase hereditary breast and ovarian cancer risk.
- Gynaecomastia is benign enlargement of male breast tissue from a relative excess of oestrogen over androgen.
- Gynaecomastia occurs physiologically in puberty and with liver disease, drugs, and hypogonadism.
Mapped competency codes
- PA31.2
- PA31.4
Continue into the full chapter
This summary maps to PA31-breast.
Frequently Asked Questions
What is the most common type of invasive breast cancer?
Invasive ductal carcinoma of no special type, which typically forms a firm stellate mass with a desmoplastic stromal reaction.
How is breast cancer classified molecularly?
By oestrogen receptor, progesterone receptor, and HER2 status, giving luminal, HER2-positive, and triple-negative subtypes that guide therapy and prognosis.
What causes the single-file pattern of invasive lobular carcinoma?
Loss of the adhesion molecule E-cadherin, which causes tumour cells to infiltrate the stroma in single-file lines.
What is gynaecomastia?
Benign proliferation of male breast glandular tissue due to a relative excess of oestrogen over androgen, seen in puberty, liver disease, and with certain drugs.
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