Breast cancer types

Question 1

In situ carcinomas

Answer 1

• Ductal carcinoma in situ
• Lobular carcinoma in situ

Question 2

Ductal carcinoma in situ

Answer 2

• Does not produce a mass but is often detected by calcification on mammography
• Histology: Malignant proliferation of ductal cells without invasion of the basement membrane.
• Subtypes: comedo and non-comedo subtypes

Question 3

Lobular carcinoma in situ

Answer 3

• Mammography normal
• Often discovered incidentally when the breast is biosied for alternate reasons
• Histology: Malignant proliferation of ductal cells without invasion of the basement membrane
• Characterised by loss of E-cadherin

Question 4

Types of invasive carcinoma

Answer 4

• Invasive carcinoma of no special type (NST)
• Tubular carcinoma
• Mucinous carcinoma
• Medullary carcinoma
• Inflammatory carcinoma
• Invasive lobular carcinoma

Question 5

Invasive carcinoma of no special type (NST)

Answer 5

• MC invasive cancer
• Presents with mass on screening
• Unilateral and unifocal
• Histology = Malignant duct-like structures without any other features.

Question 6

Tubular carcinoma

Answer 6

• No palpable lump but identified on screening
• Well-differentiated tubules
  Traditionally considered to be a subtype of invasive ductal carcinoma

Question 7

Mucinous carcinoma

Answer 7

• May present with palpable mass
• Histology: Tumour cells in a ‘lake’ of mucin
• Traditionally considered to be a subtype of invasive ductal carcinoma

Question 8

Inflammatory carcinoma

Answer 8

• Mimics mastitis: inflamed, swollen breast, Peau d’orange
• Histology: Characteristic by infiltration of dermal lymphatics
• Can arise from any subtype, but most typically arsies from invasive ductal carcinoma

Question 9

Invasive lobular carcinoma

Answer 9

• More difficult to detect on mammography due to linear growth compared to NST
• Bilateral and multifocal
• Histology: Cells grow in a single-file
• Lack of E-cadherin