The characteristic fixation of malignant tumors of the breast either to the skin or to the fascia of the pectoralis major muscle is well known. This characteristic is due to the arrangement of the areolar tissue and of the capsule of the breast. The continuity of the stroma throughout the gland forms compartments for the secreting elements. Fibrous prolongations from the stroma of the breast connect the breast in its anterior portion with the under surface of the skin and in its posterior portion with the aponeurosis of the pectoralis major muscle. Thus all tissues surrounding the breast are bound to it by connective tissue fibers which are continuous with the matrix of the breast.
Because of this peculiar structure, a malignant tumor in the breast infiltrates the matrix and causes a contraction of its fibrous elements. This contraction produces an abnormal firmness in the area of involvement. As the