Summary

Neuroendocrine breast cancer is thought to account for about 1% of all breast cancers. This rare type of breast malignancy is more common in older women and presents as a low-grade, slow-growing cancer. The most definitive markers that indicate neuroendocrine carcinoma are the presence of chromogranin, synaptophysin or neuron-specific enolase, in at least 50% of malignant tumour cells. The authors present a case report of an 83-year-old woman, admitted to their institution with right breast lump. Physical examination, mammography and ultrasonography showed a 2.4 cm nodule, probably a benign lesion (BI-RADS 3). A fine needle aspiration biopsy was performed and revealed proliferative epithelial papillary lesion. She was submitted to excisional biopsy and histology showed endocrine breast cancer well differentiated (G1). Immunohistochemically, tumour cells were positive for synaptophysin. These breast cancers are characterised for their excellent prognosis and conservative treatment is almost always enough to obtain patient cure.