As mentioned by Florida Fan and Tomáš Macháček, we can see several characteristic features of C. sinensis, including the oral sucker, esophagus, twin ceca, ova-filled uterus, lateral vitellaria, seminal receptacle and classic eggs with shouldered operculum (arrow heads). I've highlighted several of these features below:
The testes and other internal structures allow Clonorchis to be differentiated from the related fluke Opsithorchis. Clonorchiasis is usually acquired through ingestion of undercooked or raw fish and long standing disease may cause cholangiocarcinoma (possibly explaining the patient's liver mass in this case).
And now our poem from Blaine Mathison:
When you see such small eggs with an operculum
don't get caught up in a parasitological conundrum!
the testes branching out like a tree
supports a diagnosis of Clonorchis, can't you see
as does travel to Korea, where the patient hails from!