Invasive carcinoma of breast with adnexal diff erentiation of trichoblastic type

Abstract

Sarala Ravindran, Pathmanathan Rajadurai,Joshua Mohanraj Daniel, Yip Cheng Har

We present a rare distinctive variant of invasive carcinoma of breast characterized by adnexal differentiation of tumor of trichoblastic type. The neoplasm was identified in a mastectomy specimen from an 83-year-old Chinese woman. Morphologically, the trichoblastic differentiation was characterized by the formation of solid sheets and nests of basaloid cells. The tumor cells were positive for cytokeratin 5/6, BER-EP4, bcl-2, and β-catenin. Stromal cells were positive for CD10. The tumor cells exhibited a “triple negative” profile; the nuclei did not react with antibodies to estrogen and progesterone receptors but failed to show overexpression of the HER2/neu protein. The MIB-1 labeling index averaged 20%. It is hoped that this case increases awareness for this unique morphological variant of invasive ductal carcinoma.