5. Breast carcinoma Flashcards
Risk factors for breast cancer
- Race (Caucasian, Jew, Parsi)
- Age (perimenopausal)
- Socioeconomic status (high)
- Weight (obese)
- Previous breast disease
- Family history of breast cancer
- BRCA1 & BRCA2 (DNA repair genes for double strand breaks) mutations account for 25% of familial breast cancers - Ovarian activity (early menarche, late menopause)
- Exogenous estrogen (oral contraceptives, hormone replacement therapy)
- Nulliparity
- Lack of breastfeeding
- Proliferative diseases of the breast
Classification of breast cancers
- Carcinoma-in-situ
a. Ductual carcinoma-in-situ (+ Paget’s disease)
b. Lobular carcinoma-in-situ - Invasive carcinoma
a. Invasive ductal carcinoma
b. Invasive lobular carcinoma
c. Special types: tubular, mucinous, medullary
Clinical presentations of breast cancer
- Palpable mass
- Nipple discharge (serous or bloody)
- Mammographic density & calcifications
- Nipple retraction
- Peau d’ orange appearance
- Lymphedema of the breast secondary to disruption of lymphatic drainage of breast by tumour deposits
- Tethering of skin of breast by Cooper ligaments in the setting of lymphedema produces a dimpled appearance → peau d’ orange - Lymph node metastates (palpable axillary metastases)
Prognostic factors for breast cancer
- Tumour size
- <2 cm better, >2cm worse - Tumour grade
- Well-differentiated better - Axillary nodes
- None or few better, many worse - Estrogen receptors
- Present better
- Can treat with estrogen antagonists (tamoxifen) or
aromatase inhibitors
- However, ER+ tumours are less likely to respond to
chemotherapy - HER2/neu receptor
- Present worse
- Can treat with tyrosine kinase inhibitors
(trastuzumab aka herceptin or lapatinib) - DNA amount
- Diploid better, aneuploid worse - Histologic type
- Lobular & special types better, ductal worse - Tumour staging
- Lower stage better - Vascular invasion
- Present worse
Histological types of ductal carcinoma-in-situ
- Comedo type
- Cribriform type
- Solid type
- Papillary type
- Micropapillary type
- May give rise to Paget’s disease
Morphology of comedo type DCIS
- Solid sheets of pleomorphic cells
2. Areas of central necrosis (debris often calcify & appear on mammographs as linear & branching microcalcifications)
Morphology of cribriform type DCIS
- Intraepithelial spaces evenly distributed & regular in shape (cookie cutter appearance)
- Lumen filled with calcifying secretory material
Morphology of solid type DCIS
- Completely filled involved spaces
2. Not usually associated with calcifications (hence may be clinically occult)
Morphology of papillary type DCIS
- Grows into spaces along fibrovascular cores
- Lack myoepithelial layer
- Fibrovascular cores lined by monomorphic columnar cells
Morphology of micropapillary type DCIS
- Bulbous protrusions lacking fibrovascular cores (solid papillae)
- Narrow stalks
Lobular carcinoma-in-situ
Associated with E-cadherin mutation (also seen in invasive lobular carcinoma & signet-ring cell gastric adenocarcinoma)
Morphology of lobular carcinoma-in-situ
- Dyscohesive cells with round nuclei & small nucleoli
2. May have signet ring cells
Presentation of DCIS
- Incidental finding
- Mammographic density
- Nipple discharge
- Paget’s disease
- Palpable mass
Predominant location of DCIS
Ducts
Cell size in DCIS
Medium or large
Histological types of DCIS
Comedo, cribriform, solid, papillary, micropapillary
Calcifications in DCIS
Present or absent
Risk of subsequent invasive breast cancer in DCIS
Higher than LCIS
Location of subsequent invasive breast cancer in DCIS
Ipsilateral
E-cadherin expression in DCIS
Higher than LCIS
Receptor expression in DCIS
variable
Presentation of LCIS
Incidental finding (as it is not associated with calcifications or stromal desmoplastic reactions that produce mammographic densities)
Predominant location of LCIS
Lobules
Cell size in LCIS
Small
Histological type in LCIS
Solid
Calcifications in LCIS
Usually absent
Risk of subsequent invasive breast cancer in LCIS
Lower than DCIS
Location of subsequent invasive breast cancer in LCIS
Ipsilateral or contralateral
E-cadherin expression in LCIS
Lower than DCIS
Receptor expression in LCIS
ER+, PR+, HER2/neu-
Definition of Paget’s disease
Rare manifestation of Ductal Carcinoma-In-Situ involving the nipple
Pathogenesis of Paget’s disease
Extension of DCIS along ducts within the epithelial layer
to the area under the skin over nipple
Appearance of Paget’s disease
- Unilateral
- Exfoliation/ulceration of nipple
- Erythematous eruption with a scale crust
Definition of invasive ductal carcinoma
A ‘wastepaper basket’ category of invasive breast carcinomas that encompasses all breast cancers not classifiable under the other types
Molecular classification of invasive ductal carcinoma
- Luminal A (40-55%)
- Luminal B (15-20%)
- Normal breast-like (6-10%)
- Basal-like (13-25%)
- HER2 positive (7-12%)
Luminal A invasive ductal carcinoma
- ER+, HER2/neu-
2. Slow-growing, responds well to hormonal treatment
Luminal B invasive ductal carcinoma
- ER+, HER2/neu+
- Higher grade, higher proliferative rate
- More likely to have lymph node metastases
- May respond to chemotherapy
Normal breast-like invasive ductal carcinoma
- ER+, HER2/neu-
- Pattern of gene expression similar to normal breast
- Well-differentiated
Basal-like invasive ductal carcinoma
- ER-, PR-, HER2/neu-
- Express myoepithelial markers (basal keratins, P-cadherin, p63, laminin)
- High grade, high proliferative rate
- Aggressive, metastases to brain & viscera
- BRCA1 associated
HER2 positive invasive ductal carcinoma
- ER-, HER2/neu+
- Usually with HER2/neu gene amplification
- Poorly differentiated, high proliferative rate
- High frequency of brain metastases
Morphology of invasive ductal carcinoma
- Grossly:
- Hard firm mass with irregular border - Histologically: (a range possible)
- Well differentiated (tubule forming, small round nuclei)
- Moderately differentiated (tubules & solid clusters, mitotic figures, more nuclear pleomorphism)
- Poorly differentiated (ragged nests/solid sheets of cells with enlarged irregular nuclei)
Associations with invasive lobular carcinoma
E-cadherin mutation (also seen in lobular carcinoma-in-
situ & signet-ring cell gastric adenocarcinoma)
Morphology of invasive lobular carcinoma
- Grossly:
- Mass with irregular border
- In 1⁄4 of cases, tumour infiltrates diffusely & causes little desmoplasia - Histologically:
- Dyscohesive infiltrative tumour cells often arranged in a single file/loose clusters/sheets
- No tubule formation
- Minimal/no desmoplasia
- May have signet-ring cells
Clinical features of invasive lobular carcinoma
- Unique pattern of metastasis (peritoneum & retroperitoneum, leptomeninges, GIT, ovary & uterus)
- Rare heterozygous germline mutation of E cadherin gene resulting in genetic predisposition to:
- Invasive lobular carcinoma
- Signet-ring cell gastric adenocarcinoma
Morphology of tubular carcinoma
- Small irregular masses
- Well-formed tubules but without myoepithelial cell layer
- May see cribriform pattern, apocrine metaplasia or intraluminal calcifications
Clinical features of tubular carcinoma
- Diploid
- ER+, HER2/neu-
- Well differentiated
- Axillary metastases in <10%
- Excellent prognosis
Morphology of mucinous carcinoma
- Well circumscribed
- Soft, rubbery, pale grey-blue
- Tumour cells arranged in clusters & small islands within large lakes of mucin
Clinical features of mucinous carcinoma
- Usually diploid
- ER+
- Well to moderately differentiated
- Lymph node metastases uncommon
- Better prognosis than invasive ductal carcinoma
Morphology of medullary carcinoma
- Well-circumscribed, soft, fleshy
- Little desmoplasia
- Solid syncytium-like sheets of large cells with vesicular pleomorphic nuclei & prominent nucleoli
- Frequent mitotic figures
- Lymphocytic infiltrate
- Pushing non-infiltrative borders
- Poorly differentiated
Clinical features of medullary carcinoma
- ER-, PR-, HER2/neu-
- BRCA1 associated
- E cadherin overexpression
- Hence increased cell-cell adhesion
- Explains low rates of metastases, pushing non-infiltrative borders & syncytial growth pattern - Lymph node metastases infrequent
- Better prognosis than invasive ductal carcinoma