Fig. 3

The cellular morphology and immunohistochemistry of the tumour under optical microscope. A HE staining shows large, polygonal tumor cells with abundant cytoplasm and aberrant nuclei. The tumor cells are arranged in adenoid and tubular patterns (arrow), × 200. B α1-ACT immunohistochemistry staining showed diffuse positive tumor cells, suggesting a certain diagnostic significance, × 200. C AB-PAS staining, suggesting that the tumor cells secreted mucus, and the tumor originated from salivary glands, × 200. D Ki-67 immunohistochemistry staining showed a low proliferation index, indicating a low grade malignant tumor, × 200