Fig. 1

Histologic features in breast cancer with signet ring cell differentiation (hematoxylin and eosin, magnification × 400). A In case 1, signet ring-like cancer cells have abundant intracellular mucus, the nucleus is squeezed and displaced. Some nuclei are round, oval, or even crescent-shaped, resembling fat vacuoles. B Cancer cell clusters can be seen in the blood vessels of the local area in case 1. C In case 2, the signet-ring-like cancer cells had less intracellular mucus, slightly deviated nuclei, greater nuclear atypia, deeper staining, some cells were crescent-shaped. D In case 3, the intracellular mucus was abundant, the nucleus was squeezed and displaced, and some nuclei were round, oval, and crescent-shaped. E In case 4, signet ring-like cancer cells have abundant intracellular mucin, eccentric nuclei, round, irregular, or crescent-shaped nuclei. F In case 5, signet ring-like cancer cells have abundant intracellular mucus, eccentric nuclei, round, fusiform or comma-shaped nuclei