The present chapter provides a basic pictorial introduction to breast pathology for the surgeon. It aims to assist him or her in understanding and visualizing the breast lesions discussed elsewhere in this book. Only the lesions most commonly encountered by a general pathologist are covered. For an in-depth discussion of breast pathology, including discussions of the more unusual breast diseases, readers are encouraged to consult textbooks on breast pathology (see Suggested Readings section).

OVERVIEW OF THE PATHOLOGIST'S ROLE

After physical examination reveals the presence of suspicious palpable lesions, or after mammography or other imaging studies reveal the presence of occult non-palpable abnormalities, a definitive diagnosis of cancer or benign breast disease rests with a histologic examination of the tissue. In addition to confirming the presence or absence of malignancy, the pathologist looks for morphologic features that help to predict the aggressiveness of a particular tumor, describes the extent and spread of disease, and indicates the adequacy of the surgical excision.

Pathologic features help to guide the surgeon, oncologist, and radiation therapist in planning therapy and in predicting prognosis. Morphology remains the most important pathologic feature in prognosis, but it is supplemented by important biologic, molecular, and genetic parameters that predict the behavior of a tumor and its response to various therapies. Examination of tissue may reveal lesions that, although still benign, increase the patient's risk of developing a malignancy.