Apocrine carcinoma of the breast. Clinical, histological and immunohistochemical features

Abstract

Introduction. Invasive apocrine carcinoma of the breast is a rare special subtype of mammary carcinoma and accounts for 0.3-1% of all breast malignancies. It has specific histological, immunohistochemical, and molecular genetic characteristics. The tumour cells have a unique immunohistochemical profile, which is to show Gross Cystic Disease Fluid Protein 15 (GCDFP-15) and androgen receptor (AR) positivity, as well as estrogen (ER), progesterone (PR), and Human Epidermal Growth Factor Receptor 2 (HER2) negativity. Case presentation. We report a case of invasive apocrine carcinoma in a 55-year-old female with a lump in the right breast and no axillary lymphadenopathy. Lumpectomy and sentinel node biopsy were performed. The histological examination and the immunohistochemical profile confirmed the diagnosis of invasive apocrine carcinoma with micro metastasis in sentinel lymph node which, to our knowledge, is the first published case. Due to the involvement of one of the resection lines from high grade apocrine ductal carcinoma in situ (DCIS), the patient underwent right modified radical mastectomy with axillary dissection. Conclusions. This report is a rare specific morphological type of invasive apocrine carcinoma with micro metastasis in sentinel lymph node. The unique immunohistochemical profile, the possibility of an anti-AR therapy, and the favorable prognosis separate it from basal-like triple-negative breast cancers.

Keywords

• breast cancer
• invasive apocrine carcinoma
• pathology
• immunohistochemistry