A systematic study on 33 gallbladder stones resembling adult Clonorchis sinensis worms

Limited studies provide direct evidence of Clonorchis sinensis adults in the early stage of gallbladder stone formation. Our current research systematically studied 33 gallbladder stones resembling adult worms and shed light on the definite connection of C. sinensis infection with concomitant cholelithiasis. A total of 33 gallbladder stones resembling adult C. sinensis worms were systematically analysed. Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray energy spectrometry were used to analyse the composition and microstructure. Meanwhile, a histopathological examination of the stone was carried out. The 33 gallbladder stones resembling adult C. sinensis worms included nine calcium carbonate (CaCO₃) stones, 12 bilirubinate stones and 12 mixed stones. Clonorchis sinensis eggs were found in 30 cases, including all CaCO₃ and mixed stones. Parasite tissues were detected in 12 cases, which were mainly CaCO₃ stones or bilirubinate-CaCO₃ mixed stones. The outer layer of stones was wrapped with 12.88% calcium salt, as revealed by X-ray energy spectrometry, while surprisingly, many C. sinensis eggs were found in the inner part of these stones. Based on our current findings, we concluded that calcification and packaging occurred after C. sinensis adult entrance into the gallbladder, subsequently leading to the early formation of CaCO₃ or bilirubinate-CaCO₃ mixed gallbladder stones. This discovery highlights definite evidence for C. sinensis infection causing gallbladder stones.