An Uncommon Cause of a Breast Mass in a Child: Periductal Stromal Hyperplasia

Periductal stromal hyperplasia (PDSH) is a biphasic breast tumor characterized by spindle stromal cell proliferation. Fewer than 15 adult cases have been reported in the literature. A 14-year-old girl presented with swelling in axillary tail of the right breast persisting for 3 months. Ultrasonography was compatible with accessory breast tissue in both axillary regions. Macroscopic examination revealed 3x2x1 cm, non-encapsulated nodular lipomatous mass. Cut surface showed thin fibrotic bands through the adipose tissue. The major histopathological feature was spindle cell stromal cell proliferation concentrated around the ducts. There is no local recurrence during postoperative fourteen months. PDSH is a rare lesion frequently observed in older women. It has no specific clinical and radiological features. Definitive diagnosis can be made by histopathological examination of excision materials. The PDSHs do not show phyllodes tumor features. The spindle cells concentrating around ductal areas don't show marked atypia, demonstrate fewer mitosis and low proliferation index. Present case report is important in terms of unexpected age group and localization. PDSH should be kept in mind as a differential diagnosis of accesory breast tissue in children with axillary lump.