Review of axillary lesions, emphasising some distinctive imaging and pathology findings.

The axilla is often included on mammography, ultrasound (US), CT and MRI. Axillary masses can arise from any of the tissue components present in this region including breast parenchyma. Aetiologies include: lymphadenopathy due to inflammation, malignancy and degenerative causes; soft tissue tumours such as haemangioma, lymphangioma, peripheral nerve sheath tumours and lipomas; post-surgical complications such as seroma, lymphocoele and haematoma; lesions arising in accessory breast tissue such as fibroadenoma and carcinoma. Some of these entities have distinctive imaging appearances knowledge of which can be helpful in suggesting the correct diagnosis.