Blastocystis hominis in Hepatic Abscesses: Innocent Bystander or Hidden Culprit? A Case Report and Literature Review

Blastocystis hominis is a ubiquitous intestinal parasite commonly detected in human stools. Queries about the pathogenic nature of B. hominis in immunocompetent individuals have been raised with conflicting reports about the clinical significance of detecting the parasites in various specimens. Reports have documented invasive intestinal infections and detection of Blastocystisspecies in both a splenic cyst and a hepatic abscess. We present the case of a 65-year-old man with history of recent travel to a tropical country who was found to have multiple hepatic abscesses. Analysis of the hepatic abscess fluid confirmed the presence of Entamoeba histolytica and Blastocystis species, and to our knowledge, this is the second reported case of the same findings. Overall, the clinical and microbiological picture was most consistent with amoebic liver abscess secondary to E. histolytica, however, the presence of Blastocystis species introduces uncertainty around its clinical significance. Further studies are required to investigate the pathogenicity of Blastocystis species, including molecular investigations into the various genetic subtypes.