ADENOID cystic carcinoma of the breast is a tumor seen by few surgeons. It has been described as a "vanishingly rare tumour."1 A survey of 2,623 malignant breast tumors provided only four examples.2 In addition to its rarity, it is a distinct form of carcinoma in that it is slow growing and lymph node metastases rarely occur. The tumor has been variously called cylindromatous carcinoma, adenocystic basal cell carcinoma, cylindroma, and adenoid cystic carcinoma of the breast.3 We report a patient with adenoid cystic carcinoma which was found incidental to the investigation of a duct papilloma. Report of Case A 63-year-old Negro woman was admitted to the University College Hospital of the West Indies on Dec 3, 1964. In 1953 a clinical diagnosis of chronic cystic mastitis had been made. She complained of a painless lump in the left breast which had been present for ten years