A 49-year-old male patient presented to the emergency department with acute onset of painful swelling in the left breast. An unusual diagnosis of breast abscess was made using ultrasound scan, incision and drainage were performed followed by antibiotics, with full recovery.

A 56-year-old nulliparous woman presented to the emergency department with acute onset of redness, sensitivity, and local fever in the left breast. Mastitis with abscess was diagnosed. Unusual pathogens were identified in the culture obtained from the abscess - Proteus mirabilis and Prevotella buccalis. Keywords: breast abscess; Proteus mirabilis; Prevotella buccalis.