EXPRESSION OF KIT IN ADENOID CYSTIC CARCINOMA OF THE BREAST

Abstract

Adenoid cystic carcinoma of the breast is a rare entity and is designated as specific breast cancer. This paper deals with such a rare case of adenoid cystic carcinoma of the breast with some consideration on the results of immunostaining with KIT which was added in this case. The patient was an 81-year-old woman complaining of a right breast mass. On mammography, the tumor was visualized as a tumor shadow of high density. Ultrasonography showed some cystic portions in the tumorous shadow. At surgery, extirpation of the tumor and sampling of the right axillary lymph nodes were performed. Histopathological studies demonstrated adenoid structure and false ductal structure, so that adenoid cystic carcinoma of the breast was diagnosed. No metastatic lymph nodes were involved in the sampled nodes.
In this case the tumor cells were negative for estrogen and progesterone receptors (ER and PgR), while positive for Vimentin and KIT. There have been no reports on expression of KIT in adenoid cystic carcinoma of the breast like in this case in Japan. Thus we consider that such very specific immunological trait can contribute to make differentiation of the disease from other breast cancers. Further the prognosis of this malignancy is favorable and once a complete excision of the local lesion is carried out, axillary lymph node dissection may not be demanded.