Mammograms performed at the Diagnostic Imaging Department of the "Instituto Brasileiro de Controle do Câncer" (IBCC - Brazilian Cancer Control Institute) will be prospectively evaluated. Patients who present a solitary dilated duct visualized by mammography will be submitted to breast ultrasonography. In case of detection of lesion, a percutaneous biopsy will be performed.

Purpose: To determinate the incidence, pathological significance and risk factors associated with the presence of solitary dilated duct visualized at mammography exam.

Methods: Mammograms performed at the Diagnostic Imaging Department of the "Instituto Brasileiro de Controle do Câncer" (IBCC - Brazilian Cancer Control Institute) will be prospectively evaluated. Patients who present a solitary dilated duct visualized by mammography will be included in the study. These patients will be recalled in order to be submitted to an ultrasonography directed to the mammographic finding. Patients who present lesions on ultrasonography will undergo method-guided percutaneous biopsy.

Patients with ductal ectasia, without evident lesions, will be followed for 2 years to evaluate stability by means of mammography or ultrasonography every 6-month intervals.

Inclusion Criteria:

• Identification of a solitary dilated breast duct at mammography

Exclusion Criteria:

• Previous breast surgery at same side of detection of dilated duct

Women submitted to mammography for breast cancer screening or for diagnosis purposes