Which malignant pathology has a presentation very similar to mastitis and must be ruled out?

• A. Inflammatory breast cancer
• B. Ductal carcinoma in situ
• C. Lobular carcinoma
• D. Fibroadenoma

Answer: (A)

Inflammatory signs in the breast that look like an infection can actually be due to a cancer that masquerades as mastitis. Inflammatory breast cancer tends to present with rapid onset redness, warmth, swelling, tenderness, and skin changes such as edema or peau d’orange, which are easily mistaken for mastitis, especially in the peripartum period. A key clue is that these symptoms may progress quickly or persist despite antibiotics, and imaging often shows diffuse skin thickening and dermal edema rather than a single, well-defined mass.

On ultrasound you may see thickened skin and interlobular septal thickening with edema, sometimes with no discrete mass, or with an ill-defined lesion if a tumor is present. Because of its inflammatory presentation, this malignancy must be ruled out whenever mastitis-like symptoms fail to improve or when there are atypical imaging features.

The other entities are less likely to mimic an inflammatory, rapidly evolving clinical picture. Ductal carcinoma in situ usually presents with microcalcifications on mammography and little to no inflammatory change. Lobular carcinoma often appears as subtle thickening or diffuse changes rather than an acute inflammatory presentation. Fibroadenoma is a benign, well-circumscribed lesion typical in younger patients, not a cause of acute breast inflammation.