What symptom is primarily associated with mammary ductal ectasia?

Mammary ductal ectasia is characterized by the dilation and stagnation of the milk ducts beneath the nipple, often leading to a build-up of thick, sticky fluid. This condition frequently results in nipple discharge, which is typically thick and can be greenish or black in color. The discharge is often a key clinical feature that prompts patients to seek medical attention.

While other symptoms such as painful breast swelling, palpable lumps, or skin changes can occur in breast conditions, they are not the hallmark symptom of mammary ductal ectasia. The presence of nipple discharge is what primarily distinguishes this condition, making it the most indicative symptom. In many cases, the discharge can occur without associated pain or significant changes to the breast tissue, although some patients may experience mild symptoms.