Page 542 - Concise Pathology for Exam Preparation ( PDFDrive )

19 The Breast 527

(b) HER2-positive; may be ER-positive or -negative (10–20% tumours)
• Associated with amplification of HER2 gene on chromosome 17 (Flowchart 19.2).

Germline TP53 mutations
Normal breast Atypical apocrine adenosis DCIS
HER2 amplification

HER2-positive carcinoma
FLOWCHART 19.2. Pathway of development of HER2-positive carcinoma breast.

Salient features:
• Affect young women who are TP53 mutation carriers
• Histologically, some may be apocrine type
• Survival ,10 years; ER-negative cancers respond to chemotherapy in .30% cases
whereas ER-positive cancers respond to about 15% (triple-positive tumours are
generally of higher grade).
(c) ER-negative; HER2-negative (10–20% tumours)
• Arise from a pathway independent of ER-mediated changes (Flowchart 19.3).

Germline BRCA1 mutations
Normal breast DCIS ER-negative, HER2-negative carcinoma
TP53 mutations
FLOWCHART 19.3. Pathway of development of ER-negative, HER2-negative carcinoma
breast.

Salient features:
• Affect young women who are TP53 mutation carriers
• Triple-negative; high grade; poorly differentiated; poor prognosis
• Histological types include medullary, adenoid cystic, secretory and metaplastic
2. Histological classification
(a) Noninvasive: Lesions that are confined to ducts and lobules and have not penetrated
the limiting basement membrane. They can be further classified into
• Ductal carcinoma in situ (DCIS)
• Lobular carcinoma in situ (LCIS)
(b) Invasive: Lesions that have penetrated the limiting basement membrane. These
include
• Invasive carcinoma of no special type (NST)
• Invasive lobular carcinoma
• Medullary carcinoma
• Mucinous (colloid) carcinoma
• Tubular carcinoma
• Metaplastic carcinoma
• Inflammatory carcinoma
• Other types

Risk Factors for Carcinoma Breast
• Age: Rare before 25 years, except in familial cases, peaks at 70–80 years and then
declines in incidence. Menarche at age ,11 years increases risk by 20% as compared to
menarche at age .14 years.
• Geography: Six times higher incidence in developed countries but rising incidence in
developing countries.

mebooksfree.com