Editing Benign breast lesions (section)

== '''Non-proliferative''' (RR of lifetime breast cancer ~1.2-1.4x) ==

=== '''Breast cysts''' ===

** Pathophysiology
*** Fluid-filled, round or ovoid masses derived from the terminal duct lobular unit, lined with epithelium
*** Appear to arise from destruction and dilatation of lobules and terminal ductules - possibly fibrosis at or near the lobule, leading to expansion of a cavity if fluid continues to be secreted
*** Influenced by ovarian hormones
*** Vary in size from microscopic to large palpable masses containing up to 30mL of fluid
*** Intra-cystic cancer is found in 0.1% of aspirations (Sabiston)
** Clinically
*** Palpable abnormality or cause of pain
*** Well-circumscribed borders, benign-feeling
*** 50% are multiple or recurrent
*** Common in women between 35 and 50 years old, rare after menopause (can occur with HRT)
*** Fluid can be straw-coloured, opaque, or dark green, and may contain debris
** Diagnosis
*** USS to diagnose
**** Simple cyst - well-circumscribed, no septations or debris, thin walled
**** Complex - septations, solid component, thick wall
** Management
*** Asymptomatic simple cysts - no intervention, reassure, does not need to be aspirated
*** Symptomatic simple cysts - observe or aspirate (if bloody aspirate, get cytopathology to exclude malignancy)
**** Remember, aspiration can change the architecture permanently, as a scar component can develop, making it harder to interpret future images (according to one breast surgeon)
*** Complex cysts - aspiration for cytology
**** Recurrence twice: consider tissue biopsy of solid elements (USS-guided with clip left in place)
*** Entire cyst can be removed with a vacuum-assisted core needle device
*** Surgical removal indications:
**** Multiple recurrences
**** Large and painful
**** Atypia on biopsy
**** Incomplete percutaneous removal

=== Galactocoele ===

** Cystic collections of fluid, usually caused by an obstructed milk duct or inspissated milk within ducts
** Generally occurs right after feeding has stopped or declined, but can occur 6-10 months after breastfeeding has ceased
** Soft cystic masses on exam, usually found centrally or under the nipple
** Mammography: indeterminate mass, may have classic fat-fluid level
** USS may show a complex mass
** Aspiration - thick, creamy material that may be tinged dark green or brown (appears purulent but is in fact sterile)
** Treatment with large-bore needle aspiration
** Excision is not necessary unless the cyst cannot be aspirated or becomes infected
** No increased risk of cancer

=== Papillary apocrine change ===

** Proliferation of ductal epithelial cells showing apocrine features, characterised by eosinophilic cytoplasm

=== Epithelial-related calcifications ===

=== Mild hyperplasia of the usual type/mild ductal hyperplasia ===

** Increase in the number of epithelial cells within a duct that is more than two, but not more than four, cells in depth. Epithelial cells do no cross the lumen of the involved space.
** Differentiate from florid ductal hyperplasia - less quantity

=== Columnar cell change/simple columnar alteration ===

** Change of cuboid epithelium to columnar in lobules
** <2 cell layers