This patient with a breast abscess is being prepared for surgical drainage of the abscess. A biopsy will be done to exclude carcinoma. Because milk is an excellent culture medium, the breast must be kept empty. These simple milk-filled cysts probably form because of ductal obstruction. The patient complains of a tender mass, usually peripheral in the breast.
Needle aspiration is both diagnostic and curative.
These benign tumors often increase in size during pregnancy, sometimes dramatically. Occasionally the lesion outgrows its blood supply and infarcts. Both rapid growth and infarction may be associated with pain and a mass difficult to distinguish from cancer. Such calcifications may be the remnants of asymptomatic infarcts. This is the gross appearance of a typical mammary hamartoma.