These are images of lobular breast carcinoma (liquid-based preparation, SurePath). Lobular breast cancer presenting in an atrophic background pattern can be challenging. Small clusters of cells (a) and individual cells (b) with mucin vacuoles contrast with a background of parabasal cells. Confirmation with immunostains can be helpful, including gross cystic disease fluid protein 15 (c) and estrogen receptor immunocytochemistry (d) (From: The Bethesda System for Reporting Cervical Cytology. Nayar R, Wilbur DC, (Eds), 3rd Edition, Springer, 2015.).