ABSTRACT

Apocrine carcinoma of the breast is defi ned as a carcinoma showing cytological and immunohistochemical features of apocrine cells in >90% of the tumour cells. Although immunohistochemical studies using anti GCDFP-15 gave confl icting data with an incidence ranging from 12% to 72%, GCDFP-15 is a putative marker of apocrine diff erentiation. All types of breast carcinoma can display apocrine diff erentiation to some extent. Histochemical and immunohistochemical fi ndings are particularly important as some histiocytic tumours, oncocytic carcinoma and granular cell tumour can mimic apocrine carcinoma. Here, we discussed the histopathological, histochemical and immunohistochemical fi ndings of 6 apocrin carcinoma cases. Among them, one case was a rare type of apocrine carcinoma, namely myoblastomatoid (histiocytoid) carcinoma. A case of apocrine carcinoma of a male breast is also reported.