Xiaoying Xu, Qingling Lin
Amebic liver abscess (ALA), caused by Entamoeba histolytica, is the most common extraintestinal manifestation of amebiasis. However, in contemporary clinical practice, diagnosis increasingly relies on serology and polymerase chain reaction (PCR), whereas direct microscopic identification of motile trophozoites in aspirated specimens has become rarely documented. Furthermore, optimal management necessitates complete anti-amebic therapy covering both invasive tissue stages and luminal intestinal colonization to prevent relapse. Here, we report a case of a 25-year-old male with a history of splenectomy and pulmonary tuberculosis, presenting with fever, right upper quadrant pain, and cough. Imaging revealed a right hepatic lobe abscess. While abscess and blood cultures remained sterile, sputum culture grew E. coli. Fresh microscopic examination of the aspirate readily demonstrated motile, erythrophagocytic trophozoites, subsequently confirmed as E. histolytica by sequencing. Although the patient showed initial clinical improvement with metronidazole, he later developed severe bleeding and ulceration of the ascending colon, ultimately requiring partial colectomy. This case underscores the enduring diagnostic value of conventional wet-mount microscopy in the molecular era, offering a rapid and cost-effective tool. Critically, it also highlights a key therapeutic principle ALA treated with a tissue-active agent must be followed by a luminal agent to eradicate intestinal carriage. Failure to do so risks persistent colonic disease, severe complications, or treatment failure, as observed in this patient.