Background: Amoebiasis, an infectious disease caused by the parasitic protozoan E. histolytica, is easily misdiagnosed due to its declining incidence and atypical symptoms.
Case Presentation: A 31-year-old male presented to the hospital with dyspnea and inability to lie flat. Imaging studies indicated a large amount of pleural effusion on the right side and multiple huge cysts in the liver. The patient underwent liver tumor resection surgery at another hospital due to suspected malignancy, but no evidence of relevant malignant tumors was found in the pathological examination. Subsequently, we performed metagenomic next-generation sequencing on the liver drainage fluid and obtained liver pathology slides from the hospital where the surgery was performed at that time. Both of them confirmed the diagnosis of amoebic infection. Empirical treatment with metronidazole was initiated before the diagnosis was confirmed, along with symptomatic treatments such as thoracic drainage and liver drainage. Eventually, the patient’s condition improved and he was discharged smoothly.
Conclusion: In order to avoid misdiagnosis of amoebiasis, thoroughly inquiring about the patient’s medical history, shifting perspectives and continuing investigating are necessary when one diagnostic approach proves ineffective. Besides, interdisciplinary collaboration and persistent efforts are crucial for accurate diagnosis.

Keywords: amebiasis, amoebic abscess, diagnosis, HIV, metagenomic next-generation sequencing, metronidazole