Which benign breast condition is characterized by dilated lactiferous ducts filled with cellular debris?

Mammary duct ectasia is characterized by the dilation of lactiferous ducts, which can become obstructed and filled with cellular debris, leading to inflammation. This condition often occurs in women who are nearing menopause and can present with symptoms such as a thick, sticky discharge from the nipple, tenderness, and even pain. The obstruction results in the accumulation of fluid and debris, causing the ducts to dilate further.

In contrast, intraductal papilloma typically presents as a small growth within the duct but is not primarily characterized by the dilation of ducts filled with debris. Phyllodes tumor is a rare fibroepithelial tumor that can occur in the breast, but it is not classified under benign duct conditions and does not involve dilated ducts specifically. Fat necrosis involves local damage to fat tissue resulting in oil-filled cysts, not ductal changes. Thus, the specific characteristics of mammary duct ectasia align directly with the clinical description presented in the question, confirming it as the correct answer.