Aims: To report five cases of a rare variant of intraductal carcinoma of the breast, so-called cystic hypersecretory carcinoma. The clinical and pathological characteristics of the lesion are described, along with a review of the literature.
Methods and results: The patients were females aged between 53 and 78 years (average 66.8 years). The size of the lesions ranged between 70 and 80 mm in largest dimension. In two cases, the development of high-grade invasive ductal carcinoma was observed; in one additional case there was recurrence of high-grade in-situ carcinoma after 3 years. This emphasizes the importance of correct diagnosis of this potentially aggressive lesion. Strong over-expression of HER-2/neu protein was observed in three cases, including the two with an invasive component. Protein p53 was variably positive in all cases. Steroid receptor immunohistochemistry yielded variable results with only one case being positive for both oestrogen and progesterone receptors. Interestingly, in most cases (4/5) staining for androgen receptors was observed.
Conclusions: Cystic hypersecretory ductal carcinoma of the breast is a rare distinctive variant of ductal carcinoma in situ. It has the potential for invasive growth and the development of metastases.