We report herein a case of a 42 year old woman with adenoma of the nipple of her left breast. The diseased nipple was enlarged, reddened and a hard elastic mass was palpable within its substance. There was an area of eczematoid erosion on the surface. Incisional biopsy revealed a picture of adenoma and therefore the nipple was excised. Five years postoperatively, there has been no recurrence of the disease. To our knowledge, only thirteen cases of adenoma of the nipple have been reported in the Japanese literature. Some clinical features and treatments are discussed in a review following the case report. Although rare, adenoma of the nipple should be borne in mind to avoid a misdiagnosis of malignancy and unnecessarily extensive surgery.