Benign Breast Tumours

Types of benign tumours

Fibroadenoma

  • Most common benign growth in the breast
  • Usually occurs in women of reproductive age with peak incidence in 3rd decade but can occur at any age
  • More common in Afro-Carribbean women
  • Proliferations of stromal and epithelial tissue of the duct lobules (biphasic)
  • On examination, they are highly mobile lesions (historically termed a ‘breast mouse’) that are well-defined and rubbery on palpation, with most less than 5cm in diameter
  • Have very low malignant potential, do not need to be removed because they tend to remain unchanged or decrease in size approaching the menopause

Phyllodes tumour

  • Rare fibroepithelial tumours which most commonly affects women 40-50 years
  • Biphasic tumour dominated by stromal overgrowth
  • They often grow rapidly
  • Behaviour depends on stromal features - benign, borderline, malignant
    • Around one third of Phyllodes tumours have malignant potential
    • Prone to local recurrence if not adequately excised
    • Rarely metastasize
  • Consequently, most Phyllodes tumours should be widely excised

Hamartoma (fibroadenolipomas)

  • Circumscribed lesion composed of cell tyes normal to the breast but present in an abnormal proportion or distribution

Sclerosing lesions

  • Benign, disorderly proliferation of acini and stroma
  • Can cause a mass or calcification
Sclerosing adenosis
  • Age 20-70
  • May present with pain, tenderness or lumpiness/thickening (but can be asymptomatic)
Radial scar
  • Wide age range
  • Typically an indicental finding, can be mammographically detected
  • Mimic carcinoma radiographically
  • Probably not premalignant
    • Often show epithelial proliferation
    • In situ/invasive carcinoma may occur within these lesions
  • Management: excise or sample extensively by vacuum biopsy

Intraduct papilloma

  • Benign breast lesion that usually occur in females in their 40-50yrs, most typically occurring in the subareolar region
  • May present with nipple discharge +/- blood, or may be asymptmatic and detected on screening
  • Histology:
    • Papillary fronds containing a fibrovascular core
    • Covered by myoepithelium and epithelium
    • Epithelium may show proliferative activity - usual type hyperplasia, atypical ductal hyperplasia, ductal carcinoma in situ
  • Can appear similar to ductal carcinomas on imaging and therefore usually require biopsy
  • Some cases may be excised to ensure no atypical cells or neoplasia are present

Lipoma

  • Soft and mobile benign adipose tumour that are normally otherwise asymptomatic
  • They have low malignant potential and are usually only removed if they are significantly enlarging or causing symptomatic compressive or aesthetic issues

Investigations

  • All suspicious breast lesions should undergo the triple assessment, warranting examination, imaging, and histology

Management

  • With benign breast lumps that have been confirmed, in most cases/subtypes reassurance and routine check up appointments are sufficient
  • However, if a breast lump cannot be confirmed to be benign or has malignant potential with atypical cells, they may be excised after a triple assessment - open lumpectomy or percutaneous vacuum-assisted core biopsy
  • For some women, benign breast lumps may cause symptoms, such as pain or discomfort, if they grow and therefore excision may also be the best option