This is acute bacterial infection of the breast and may be seen at any age but typically occurs 2 to 3 weeks at start of lactation. It usually results from infection via the duct system, which may be blocked by inspissated secretions resulting in stasis. The most common organism is Staph. The infection may progress to abscess formation.
Fat necrosis occurs most frequently in women with pendulous breasts.
The typical presentation is a painless mass located superficially in the breast, accompanied by retraction or dimpling of the skin due to fibrous scar tissue extending into the adjacent tissue. They are firm to hard, fixed and irregular by palpation. A history of trauma may be elicited. Mammographic examination reveals a spiculated, often poorly defined mass lesion that may contain punctate or irregular calcifications. The lesion consists of yellow gray and focally red mass, which may contain foci of cystic degeneration filled with oily fluid or necrotic fat.