Secretory carcinoma of the breast in a nine year old boy.

Carcinoma of the breast is very rare in childhood and is exceedingly rare in boys. Secretory carcinoma, a distinctive and rare variant of breast carcinoma is for some unknown reason the commonest type seen in children. To our knowledge there have been only four previous reports in boys under ten years old. We report the first case in Australia of this unusual tumor in a nine year old boy. The child presented with a subareolar nodule 12 mm in its greatest dimension. High resolution sonography showed a well defined hypoechoic nodule. Histology revealed classical features of secretory carcinoma with circumscribed, pushing margins, except for one site of invasion. The tumor displayed the typical cribriform and microcystic pattern with PAS positive, diastase resistant secretions, and lack of pleomorphism and mitotic activity. Tumor cells showed positive staining with S100 and polyclonal CEA and negative staining for estrogen and progesterone receptors. Although, because of its rarity, the natural history of this tumor is not well documented and optimal management is uncertain, prognosis happens to be excellent as these tumors behave in an indolent manner, both in children and in adults.