case_images: PMC8813629_01
case_images: Aspiration cytology smear from larger lump shows occasional cluster of benign keratinized squamous cells (a, Giemsa x100). Papanicolaou-stained smear of the same shows benign-appearing squamous cells (b, x100).
case_images: Cytojournal-18-36-g001.jpg
case_images: PMC8813629_01_Cytojournal-18-36-g001.jpg
case_images: F1
case_images: FNA from the larger lump are shown in Figures 1a and 1b. FNA findings from the smaller lump are shown in Figures 1c and 1d.
case_images: Histopathological section shows the invasive squamous cell carcinoma component (a, H&E x100). A central cystic zone with squamous metaplasia (sq meta) and transformation to SCC and infiltration denoted as I is also seen (b, H&E x 40). The focus shown in 'b' is highlighted by immunohistochemistry for CK5/6 (c, Labeled Streptavidin-Biotin method x 40).
case_images: Cytojournal-18-36-g002.jpg
case_images: PMC8813629_01_Cytojournal-18-36-g002.jpg
case_images: F2
case_images: FNA from the smaller lump (upper outer quadrant) showed features of proliferative breast disease with the presence of stromal fragments and clusters of ductal epithelial cells showing focal mild anisonucleosis in a background of bipolar myoepithelial cells [Figure 2a]. FNA smears from the larger lump (central quadrant) showed a few inflammatory cells, an occasional cluster of benign squamous cells and histiocytes. Histopathological examination revealed features of a well-differentiated squamous cell carcinoma (SCC) comprising almost 100% of the tumor area [Figure 2b]. One of the ducts in this area had metaplastic squamous lining displaying transition to frank SCC [Figure 2c]. On immunohistochemistry, the tumor was triple-negative (estrogen receptor [ER], progesterone receptor [PR], and Her2neu) as well as negative for CK7 while being positive for pan-CK and CK5/6 [Figure 2d].