Cystic Hypersecretory Duct Carcinoma of the Breast:A Case Reprot Describing the Cytologic Features.

We report the clinical, cytological and pathological features of so-called cystic hypersecretory duct carcinoma occurring in a 60-year-old Japanese woman. The tumor mainfested a multicystic mass ultrasonographically, and aspiration biopsy cytology revealed atypical ductal epithelial cells with vacuolar cytoplasm. A modified radical mastectomy was performed. Histologically, the lesion was charcterized by many dilated ducts containing eosinophilic secretions, which resembled thyroid colloid. The ducts were lined by an intraductal micropapillary carcinoma with hobnail-shaped cells, and were positive for lactalbumin immunohistochemically. Additionally, a so-called cystic hypersecretory hyperplasia was seen in the surrounding breast parenchyma. Although a direct transition from the hyperplasia to the carcinoma was not proved, a close relationship between the two lesions was suggested.