Bloody nipple discharge in young children: mammary duct ectasia as a benign, self-limiting condition

Bloody nipple discharge in children is rare and often alarms families because of its malignant associations in adults. We describe two prepubertal boys (3 and 5 years) with unilateral, spontaneous, painless bloody nipple discharge without trauma, infection, systemic symptoms, or exogenous hormone exposure. Examinations showed only mild unilateral breast change, with no masses, skin or nipple abnormalities, or lymphadenopathy. Breast ultrasonography was the primary investigation: one child had retroareolar ductal dilatation with cystic change consistent with mammary duct ectasia; the other had normal breast architecture. When obtained, laboratory, microbiologic, and cytologic studies were unremarkable. Both patients were managed conservatively with caregiver counseling and structured clinical/sonographic follow-up. Discharge resolved spontaneously within 14 and 8 months, respectively, with complete clinical and imaging resolution and no recurrence. These cases support ultrasound-based assessment and expectant management when no concerning features are present.