Endocrine cells in a normal breast and non-cancerous breast lesion

The authors confirmed the presence of endocrine cells for the first time in a normal breast as well as in a non-cancerous lesion of the breast. One hundred and eighty-eight blocks of normal breast tissues in 44 cases and 74 blocks of non-cancerous lesions in 35 cases were examined. Argyrophil cells were found in one block from a normal breast and in one block from a phyllodes tumor. Argyrophil cells in the normal breast showed positive reaction to anti-endocrine granule constituent (EGC) antibody with immunohistochemical method. Argyrophil cells found in the phyllodes tumor gave positive reaction to both anti-EGC and anti-serotonin antibodies. The present study is thought to be the first report in the literature of serotonin-positive cells in a non-cancerous breast lesion, a phyllodes tumor.