A Case of Nipple Adenoma With Long-Term Follow-Up Without Change in Malignancy

Nipple adenomas are rare benign tumors. The risk of carcinogenesis and the exact time of cancerization of nipple adenomas is unknown. We report a case of nipple adenoma in a 76-year-old Japanese woman. At the age of 52, she noticed erosion of her left nipple and was diagnosed with nipple adenoma by biopsy at a nearby hospital. A follow-up of the left nipple lesion was performed at the patient's request; however, she refused to undergo mammography and biopsy. The patient requested surgery for the left nipple lesion after 24 years of follow-up because of increasing bloody exudates from the nipple lesion. The preoperative radiological examination did not reveal malignancy in either breast, and a left nipple-areolar resection was performed. A nipple adenoma was identified by pathological diagnosis; however, no malignant findings were observed. The present case appears to have the longest follow-up period ever reported. This case is valuable because follow-up may be a clinical management option for nipple adenomas.