Fat Necrosis

Common condition caused by an acute inflammatory response in the breast, leading to ischaemic necrosis of fat lobules

Aetiology

• Often referred to as traumatic fat necrosis due to its association with trauma (e.g. seat belt injury), however blunt trauma to the breast is only implicated in 40% cases

• Other causes include previous surgical or radiological intervention and warfarin therapy

Pathophysiology

1. Damage and disruption of adipocytes

2. Infiltration by acute inflammatory cells

3. Aggregation of ‘foamy’ macrophages

4. Subsequent fibrosis and scarring

Clinical presentation

• Usually asymptomatic or presenting as a lump, however less commonly can present with fluid discharge, skin dimpling, pain and nipple inversion

• The acute inflammatory response can persist, causing a chronic fibrotic change that can subsequently develop into a solid irregular lump

Investigations

• Fat necrosis may be suggested by a positive traumatic history and/ or a hyperechoic mass on ultrasound

• More developed fibrotic lesions will mimic carcinoma on mammogram - core biopsy is often taken to categorically rule out malignancy

Management

• Self-limiting and usually only requires analgesic management and reassurance