Unilateral Galactocele in a 2-Year-Old Boy: the Role of GATA-3

Galactoceles are benign lesions formed at the expense of breast glandular tissue. Its occurrence in boys is exceptional, with isolated reports in the scientific literature. We present the case of a 2-year-old boy who debuted with a unilateral breast enlargement of 18 months of evolution, with no other associated symptoms. Initial hormonal study showed no alterations. Ultrasonography showed the presence of a homogeneous 5-cm retroareolar cyst. Surgical excision was indicated. During the procedure, abundant milk drained from the lesion. The histopathological study, supported by GATA-3 immunohistochemical staining, confirmed the diagnosis of galactocele. The range of possible differential diagnoses for unilateral or bilateral breast enlargement in boys is wide and includes neoplastic, vascular, and hormonal etiologies. Galactocele, which is an exceptional entity in this group, should be considered. Immunohistochemical techniques such as GATA-3, characteristic of the breast epithelium, can contribute to the diagnosis.