Bilateral galactocele in a male infant with Down syndrome and congenital hypothyroidism.

Galactocele is an uncommon benign breast lesion. Its cause is unknown. Here, we report a male infant with Down syndrome and congenital hypothyroidism during the newborn period. At follow up, when he was 6 months old, bilateral mammillary swelling was detected and diagnosed as galactocele. Although thyroid hormone levels were normal, serum prolactin levels were elevated. Cyst aspiration was performed on the left side and 6 months after the aspiration of the cyst on the left side, both cysts had clinically and sonographically regressed. No recurrence was observed at the end of the 4th year.