Non-puerperal mastitis masking pre-existing breast malignancy: importance of follow-up imaging

Mastitis is an inflammatory condition of the breast with common symptoms of pain, swelling, erythema, warmth, and fever. Diagnosis of mastitis is easily made on the basis of typical symptoms and ultrasonographic findings, such as diffusely increased echogenicity of the parenchyma and subcutaneous fat, or skin thickening. However, when it occurs in women middle-aged or older, associated malignancy should be considered. In our cases, we detected irregular hypoechoic malignant masses after the disappearance of inflammatory changes. Therefore, when non-puerperal women have inflammatory signs on their breast, follow-up imaging should be performed. In particular, in the case of persistent or growing palpability after the recovery of breast inflammation, percutaneous core biopsy and short-term follow-up with ultrasonography should be considered to exclude the associated malignancy.