Erythematous Chest Wall Mass in a 2-week-old Neonate

• Neonatal mastitis is an infection of the breast tissue that presents in the first 2 months of life, with a 2:1 to 5:1 female predominance. It is most commonly caused by Staphylococcus aureus. • Common presenting signs and symptoms include erythema, warmth, and induration of the breast with or without purulent nipple discharge. • Abscess formation is a common complication of neonatal mastitis, which requires definitive management via incision and drainage or needle aspiration.