World Health Organization 4thed

Classification of Tumours of the BreastSG Jordan, SB O’Connor, TJ Lawton

Departments of Radiology and Pathology and Laboratory Medicine

Introduction Invasive Breast Carcinoma (IBC) Molecular Subtypes

Clinical Patterns

References

Acknowledgements

Fibroepithelial Tumours

The World Health Organization (WHO) establishes the standard

for histopathologic diagnoses, defining diagnoses on a per organ

system basis.

The most recent classification of breast tumors is the 4th edition

published in 2012. The publication reflects the views of a

Working Group that convened for a Consensus and Editorial

Meeting at the International Agency for Research on Cancer

(IARC), Lyon France September 1-3, 2011. 90 authors from 24

countries contributed. The end result is an authoritative

reference book that serves as the international standard for

oncologists and pathologists.

This exhibit is designed to increase radiologists’ and

technologists’ understanding of breast pathology, ie to enhance

CME and CEU at this conference.

Breast Cancer 2018

Estimated new cases and deaths from breast cancer in the US

New cases: 266,120 (female); 2,500 (male)

Deaths: 40,920 (female); 500 (male)

IBC No Special Type and Invasive Lobular Carcinoma together account for 70-90% of

invasive carcinoma tumour types. We must be knowledgeable about these and the

remaining 10-30% of invasive carcinoma tumour types. Given the sheer annual number

of newly diagnosed breast cancers, the uncommon breast tumour types ie special

tumour types will be seen in your practice.

Epithelial Tumours

Invasive breast carcinomaInvasive carcinoma of no special type

Invasive lobular carcinoma

Tubular carcinoma

Cribriform carcinoma

Mucinous carcinoma

Carcinoma with medullary features

Carcinoma with apocrine differentiation

Carcinoma with signet-ring-cell differentiation

Invasive micropapillary carcinoma

Metaplastic carcinomas

Carcinoma with neuroendocrine features

Secretory carcinoma

Invasive papillary carcinoma

Acinic cell carcinoma

Mucoepidermoid carcinoma

Polymorphous carcinoma

Oncocytic carcinoma

Lipid-rich carcinoma

Glycogen-rich clear cell carcinoma

Sebaceous carcinoma

Salivary gland/skin adnexal type tumours

Epithelial-myoepithelial tumours

Precursor lesions

Ductal carcinoma in situ

Lobular neoplasia

Intraductal proliferative lesions

Papillary lesions

Benign epithelial proliferations

Invasive NST Invasive Lobular

Tubular

DCIS

Medullary Metaplastic

Mucinous

Fibroadenoma

Phyllodes: Benign, Borderline, Malignant

Hamartoma

Lakhanii SR, Ellis IO, et al. WHO Classification of Tumours of the Breast,

4th edition. Lyon, France: International Agency for Research on Cancer

(IARC) Press 2012

Mesenchymal Tumours

WHO 4thed Broad Categories

Epithelial Tumours

Mesenchymal Tumours

Fibroepithelial Tumours

Tumours of the Nipple

Malignant Lymphoma

Metastatic Tumours

Tumours of the Male Breast

Clinical Patterns

Nodular fasciitis Myofibroblastoma

Desmoid-like fibromatosis Inflammatory myofibroblastic tumour

Lipoma Liposarcoma

Angiosarcoma Rhabdomyosarcoma

Osteosarcoma Pseudoangiomatous stromal hyperplasia

Leiomyoma Leiomyosarcoma

Benign vascular lesions - haemangioma, angiomatosis, atypical vascular

Granular cell tumour and benign peripheral nerve-sheath tumours -

neurofibroma and schwannoma

PASHMucinous Carcinoma

MyofibroblastomaLipoma

Fibroadenoma

Differences in the molecular definition of breast

carcinomas account for the heterogeneity of breast

cancer presentation and clinical course. Knowledge

of the differing tendencies of each type of breast

carcinoma assists in understanding disease prognosis

and directing care recommendations.

Molecular Subtypes 2017

Luminal A

Luminal B

Her2 enriched

Basal type

These are defined by their gene expression pattern:

Luminal are hormone receptor+ with associated

genes, distinguished as low (luminal A) or high

(luminal B) Ki67; Her2 enriched are HER2+; Basal

type are TNBC, and have catalogued clinical

patterns and treatment responses/outcomes per

subtype.

Tumours of the Nipple

Paget Disease

Nipple adenoma

Syringomatous tumor of the nipple (SyT)

Joanna Schneider UNC SOM Class of 2019

North Carolina Radiological Society

Paget Nipple adenoma

Metastatic Tumours

Tumours of the Male Breast

Defined: Tumour-like or tumour conditions

occurring exclusively in a male

Gynecomastia

Male breast cancer

Defined: Metastasis to the breast from a malignancy arising outside the breast

Wide range of extramammary malignancies can metastasize:

Haematological malignancies, Melanoma, Carcinomas of lung, ovary, prostate,

kidney and stomach, Carcinoid

In children: Rhabdomyosarcoma and Lymphoma

Mammography most commonly shows round, circumscribed mass(es) that are

rarely spiculated or calcified. These require CNB for diagnosis

Gynecomastia Male breast CA

Phyllodes Invasive Lobular DCIS

2017

NEW! in this WHO edition are 2 Clinical Patterns

BILATERAL BREAST CANCER (BBC)

Defined: primary carcinoma developing in both

breasts. One must first exclude metastasis from

contralateral cancer (CBC), pts with local, regional,

distant mets more likely to have CBC. BBC certain

if one breast is DCIS or the histologies are

different. 2-6% of breast cancers are BBC.

INFLAMMATORY BREAST CANCER

Defined: Rare but aggressive form of invasive

cancer with distinct clinical and/or pathologic

characteristics. The clinical inflammatory sx are due

to the presence of numerous dermal lymphatic

emboli, with rapid breast enlargement and skin

redness, edema, orange-peel. A skin bx is

NOT required but is helpful as it confirms dermal

lymphatic involvement. Invasive cancer NST grade

3 is the most common histologic type.

• https://seer.cancer.gov/statfacts/html/breast.html

• Dillon DA, Guidi AJ, Schnitt SJ. Chapter 28: Pathology

of Invasive Breast Cancer, in Harris JR, Lippman ME,

Morrow M, Osborne CK. Diseases of the Breast, 4th

edition, Lippincott Williams & Wilkins, 2010

• Lakhani SR, Reis-Filho JS, van de Vijer MJ.

Molecular pathology overview in Lakhani, SR, Ellis,

IO et al. WHO Classification of Tumours of the

Breast, 4th edition. Lyon, France: International Agency

for Research on Cancer (IARC) Press 2012

• Yerushalmi R, Hayes M, Gelmon K. Breast carcinoma

- rare types: review of the literature. Annals of

Oncology 20: 1763–1770, 2009

Medullary Carcinoma Invasive Micropapillary Papilloma with DCIS Invasive Carcinoma NST

GCT