Fig. 2

Macroscopic and histological findings of the salivary gland tumor. a The resected right parotid gland mass, appearing as a firm tan-colored tumor. b Well-defined nests of tumor cells varying in size are separated by a fibromyxoid stroma. (Hematoxylin-eosin, scale bar: 200 μm). c The nests are composed of small blue cells with scant cytoplasm and medium-sized cells with clear cytoplasm (insert). The normal salivary glands can be seen adjacent to the tumor nests. (scale bar: 100 μm). d Venous invasion (arrows) is evident (Elastica van Gieson staining). e Immunohistochemistry of the tumor cells shows positivity for CK8/18. f The tumor cells also show diffuse cytoplasmic positivity for desmin, although focal dot-like paranuclear positivity is also seen (inset)