Fig. 4: S-100 in breast carcinoma.
From: Novel uses of immunohistochemistry in breast pathology: interpretation and pitfalls
A high-grade ER− neoplasm with granular cytoplasm (A) may require labeling with pan-cytokeratin (AE1/AE3) to confirm epithelial differentiation (B) and labeling with nuclear GATA3 to support breast origin (C). The presence of positive nuclear and cytoplasmic S-100 labeling (D) might otherwise suggest melanoma or granular cell tumor.
