Differential Diagnosis of Masses on Mammograms Based on Density

Fatty mass on mammogram:

• Lipoma: Masses larger than 2 cm tend to be lipomas
• Fat necrosis: Seen at site of prior surgery or trauma
• Galactocele: Occur during or shortly after lactation.
• Focal breast fat simulating a mass

Mixed-density mass on mammogram:

• Fibroadenolipoma: Will contain fatty components. Looks for radiodense "capsule" when adjacent to fatty tissue.
• Intramammary lymph node: Look for fatty hilum.

Water-density mass on mammogram

• Cyst
• Fibroadenoma
• Cancer: Most tend to be more dense than surrounding fibroglandular tissue. The increased density is more apparent than real and is due to increased content of fibrous and sclerotic elements leading to decreased compressibility.

References

Sickles EA. Breast masses: mammographic evaluation. Radiology. 1989 Nov;173(2):297-303.