Breast -Reactive Epithelial Lesions

Question 1

What comprises Fibrocystic changes?

Answer 1

• Cysts
• Fibrosis
• Apocrine metaplasia
• Columnar cell changes
• Adenosis
• Most common non-proliferative lesion of the breast
• Non significant risk of cancer
• Caused by excess hormone secretion

Risk factors:
* late age menpause
* HRT
* nulliparity
* low BMI

Question 2

Describe breast cysts

Answer 2

• Single layer epithelial cells
• Outer myoepithelial cells
• Lumen may contain - Calcifications, secretions, foamy histiocytes

Question 3

Describe fibrosis

Answer 3

• Surrounds cyst wall
• Exaggerated upon repeated cyst ruptures and inflammation -> leads to scarring

Question 4

Describe Apocrine Metaplasia

Answer 4

• Eosinophilic ductal epithelial cells
• Apical snouts
• Round nuclei with conspicuous nucleoli
• May contain oxalate crystals - pale yellow, hard to see on H+E.

Question 5

Describe Columnar Cell Change

Answer 5

• Cells are perpendicularly orientated to basement membrane
• Pale eosinophilic to amphiphillic cytoplasm.

Question 6

Describe adenosis

Answer 6

• Increased acini per lobule
• Often columnar
• Seen in pregnant women
• May have stromal fibrosis

Question 7

Describe biopsy site change

Answer 7

• Organising haemorrage w/ haemosiderin-laden macrophages
• Fat necrosis - with foamy macrophages
• Foreign body giant cells/foreign body material
• Acute/Chronic inflammation
• Squamous metaplasia
• ‘Epithelial displacement’ - do not make an invasive diagnosis unless away from biopsy site

Question 8

Describe fat necrosis

Answer 8

• Necrotic adipose tissue - cystic spaces surrounded by lipid-laden macrophages
• Variable acute and chronic inflammation

* Early stage - haemorrhage and histiocyte reaction
* Late stage - fibroblastic proliferation and collagen deposition

Occurs secondary to injury following surgery, biopsy and trauma

IHC: CD68 positive histiocytes

Question 9

Describe Silicone Granuloma

Answer 9

• Many oval and empty spaces (swiss cheese)
• May or may not contain pale amorphous material
• Adjacent histiocytes/giant cells reacting to polydimethylsiloxane
• Can happen, even without frank implant rupture
• New implants - liquid silicone at body temp - migrate locally and distantly

Question 10

Describe Duct Ectasia

Answer 10

• Varying periductal inflammation
• Fibrosis
• Duct Dilation
• Lipid rich material/foamy macrophages can often infiltrate the wall
• May have squamous metaplasia
• May have Garland sign - obliterated duct lumen with recanalisation around periphery
• Primarily in perimenopausal and post-menopausal women
• Can present with pain, discharge, mass or calcification

Question 11

Describe Diabetic Mastopathy

Answer 11

• Fibroinflammatory breast lesion
• Dense, keloid-like fibrosis
• Epithelioid myofibroblasts in stroma
• B-cell lymphocytic infiltrates - CD20 positive - periductal, perilobular, perivascular
• Presents as a dense breast mass
• Often bilateral
• Characteristically presents in premenopausal women with long-standing T1DM
• Also seen in other autoimmune disorders - Grave’s, Hashimoto’s, Pernicious anemia, SLE, RA)
• Can be seen in men

Question 12

Describe IgG4 Related Mastitis

Answer 12

• Dense lymphoplasmacytic inflitrate
• IgG4 positive plasma cells (>40% IgG4/IgG ratio)
• Fibrotic stroma - storiform (Woven) pattern
• Obliterative phlebitis
• Absence of neutrophils, granulomas and giant cells is essential
• Can be bilateral
• Associated lymphadenopathy
• Occurs in middle aged females
• 50% have hypocomplementemia
• Many have substantial weight loss
• May have peripheral eosinophilia
• Other organs may be involved at time of diagnosis

Question 13

Describe granulomatous mastitis

Answer 13

• Non specific lobulocentric granulomatous inflammation
• Epithelioid and spindled histiocytes
• Multinucleate giant cells
• Central lipid vacuole
• Often has neutrophils, lymphocytes, plasma cells, eosinophils
• Can be seen in certain Corynebacterium infections
• can be seen with sarcoidosis, infection, prior procedure sites, idiopathic