4. Benign neoplasms

Question 1

Types of benign breast neoplasms

Answer 1

1. Fibroadenoma

2. Phyllodes Tumour

Question 2

Definition of fibroadenoma

Answer 2

Fibroepithelial tumour arising from intralobular stroma of breast

Question 3

Epidemiology of fibroadenoma

Answer 3

Highest prevalence in young women (peak incidence around 25 years of age)

Question 4

Morphology of fibroadenoma

Answer 4

1. Grossly:
   - Firm well-defined mobile lump (mouse in the breast)
   - May be multiple & bilateral
2. Histologically:
   - Proliferation of glandular & stromal elements (pericanalicular or intracanalicular pattern)
   - Cellular, delicate myxoid stroma (resembles normal intralobular stroma of breast)

Question 5

Clinical features of fibroadenoma

Answer 5

1. Slow-growing tumour
2. Risk of malignancy based on degree of epithelial
   hyperplasia
3. Can recur, may occasionally regress spontaneously

Question 6

Definition of phyllodes tumour

Answer 6

Fibroepithelial tumour arising from intralobular stroma of breast

Question 7

Morphology of phyllodes tumour

Answer 7

Histologically:

1. Contains both glandular & stromal components
2. Frondlike (leaf like) architecture
3. Stroma is more cellular than that in fibroadenoma
4. Not fully circumscribed, parts of tumour going into adjacent tissue (hence require 1 cm margin in excision to prevent recurrence)

Question 8

Clinical features of phyllodes tumour

Answer 8

Higher risk of malignancy than fibroadenoma
- In which it will become a sarcoma, with the proliferating stromal elements overrunning the epithelial components of the original benign tumour