Ductal dilatation as the manifesting sign of invasive ductal carcinoma

Several established mammographic criteria of malignancy are known, including the presence of a mass lesion with spiculated or irregular margins, architectural distortions, suggestive microcalcifications, and asymmetric density or breast tissue. A pattern of unilaterally dilated ducts has previously been shown to have a very low positive predictive value for cancer. The few reports of studies that have investigated the possible relationship of ductal dilatation and malignancy concluded that ductal dilatation alone cannot be an indicator of malignancy and can be deemed suggestive only when it is associated with one of the more widely accepted findings of malignancy. These include worrisome calcifications or a mass noted on mammography and clinical symptoms such as nipple discharge and a palpable abnormality. Sonography is an important tool that can be used as an adjunct to mammography for detection and staging of breast cancer, although sonographic evaluation of suggestive dilated ducts is not routine in clinical practice. In this report, we describe the mammographic and sonographic findings in a patient with multifocal invasive ductal carcinoma that manifested as unilateral dilated ducts involving a single segment, the diagnosis of which was prompted primarily by sonographic findings. A previous patient is described within the context of this report to enable comparison of these features with those of a benign breast lesion manifesting as a solitary dilated duct that proved to be a benign papilloma. To our knowledge, descriptive sonographic findings of a breast lesion suggestive of malignancy in the setting of mammographic findings of dilated ducts have not been reported.