Syringocystadenoma papilliferum: a rare breast tumor in a young boy.

Syringocystadenoma papilliferum of the breast is extremely rare in children. However, some occasional cases have been diagnosed in females. This report documents a case of syringocystadenoma papilliferum occurring in a healthy 4-year-old male. Histopathologically, this tumor, located deep in the dermis, was characterized by the presence of papillary projections extending into the lumen of epithelial cystic invaginations in a background of dense fibrous tissue. The papillary projections and the duct-like structures were lined by an inner columnar epithelium, which demonstrated luminal apical decapitation secretion, and had an outer layer of smaller cuboidal cells. These findings support apocrine differentiation in this case. A fairly dense mononuclear infiltrate in the stroma of the tumor, especially in the papillary projections, was also present. Although syringocystadenoma papilliferum is rare in children, it should not be summarily ruled out during examinations of masses found in the pediatric male breast. It is important to recognize this unusual location of the tumor so that a prompt diagnosis, based on histopathology and surgical excision, can be proposed.