Figure 2

Morphological changes of the tumor. A, The tumor infiltrated the normal skeletal muscle tissues (red arrow). B, Focally, the tumor cells showed a pattern closely resembling adenoid cystic carcinoma. C, The cells were arranged into cords or single-file arrays paralleled with each other. D, The cells surrounded the thick-walled blood vessel, and showed a characteristic constellation of features. E, Primitive chondroid matrix and cells with intracytoplasmic vacuole could be seen in focal areas. F, The tumor cells showed adenoid or microalveoli pattern in abundant basophilic matrix, and an atypical mitosis could be seen (green arrow). G, Occasionally, hyalinized, eosinophilic keloid-like collagen (black arrow) could be seen. H, Pseudovascular lumens were filled with numerous red cells. I, In extensive myxoid stroma, scarcely scattered cells could be seen.