Fig. 5
Macroscopic and microscopic findings of resected specimens. a Macroscopically, the resected tumors were smooth and well-circumscribed masses measuring about 11 cm in the upper-inner quadrant and 14 cm in the outer breast, respectively. b Lobulated lesions with slit-like spaces were observed in the cut surface. c Microscopically, sections revealed a proliferation of branching mammary ducts and hyperplastic lobules and spindle-shaped stromal cells, accompanied by hyalinized or fibro-myxoid stroma (hematoxylin–eosin staining, × 40). The features indicated juvenile fibroadenomas. There was no evidence of malignancy. d, e Immunohistochemical staining with insulin-like growth factor-2 (IGF2) antibody showed overexpression of IGF2 in the cytoplasm of ductal epithelial cells of the fibroadenoma. (d × 40, e × 100)