Identification Of Liver Fluke Eggs In Bile Duct Brush Cytology In An 82 Year Old Man With A Hepatic Mass: Report Of A Case

Abstract Introduction/Objective Clonorchis sinensis infects the liver, gallbladder, and bile ducts in humans. It is acquired via consumption of raw/undercooked fish, crabs, or crayfish in endemic areas. Though majority are asymptomatic, long lasting infections may cause severe disease. Without treatment, human infections may persist for the parasite lifespan (25–30 years). Diagnosis in cytology is challenging with a potentially acellular sample with miniscule eggs that can be overlooked as an artifact. Here we reported a rare case of liver fluke eggs diagnosed in bile duct brush cytology. Methods An 82 year old man who emigrated from China 20 years prior presented to the hospital with worsening jaundice for 2 weeks. Abdominal CT revealed a 4.8 x 2.9 cm central right hepatic lobe mass extending to the hilum, obstructing the bile ducts, resulting in severe intrahepatic ductal dilatation and stricture and focal occlusion of the right anterior portal vein. His CBC revealed eosinophilia. Bile duct brushing was submitted for cytology. Results ThinPrep and cell block showed oval-shaped parasite eggs measuring 10-24 µm. There was no other cellular matter. Eggs had a convex operculum resting on “shoulders” at the smaller end of the egg. At the opposite (abopercular) end, a small knob or hook-like protrusion was often visible. Wet mounts revealed visible miracidium inside the eggs. These findings were compatible with liver fluke eggs. Conclusion Cytologic microbiologic features of fluke eggs confirmed the findings. The most important features are the shape and size of the eggs; The seated operculum with its prominent “shoulders”, a small knob at the abopercular end, which can distinguish them from acellular artifact or a human cell. The cytologic and microbiologic features combined with the travel history and clinical presentation can aid in achieving the diagnosis.