Amebic lung abscess with coexisting lung adenocarcinoma: a unusual case of amebiasis

Amebic lung abscess with concurrent lung cancer, but without either a liver abscess or amebic colitis, is extremely uncommon. Here, we report a 70-year-old man presenting with pulmonary amebiasis and coexisting lung adenocarcinoma. During his first-time hospitalization, the diagnosis of lung amebiasis was confirmed by morphological observation and PCR in formalin-fixed and paraffin-embedded sediments of pleural effusion. Almost four months later, the patient was readmitted to hospital for similar complaints. On readmission, lung adenocarcinoma was diagnosed by liquid-based sputum cytology and thought to be delayed because coexisting amebic lung abscess. This case demonstrated that sediments of pleural effusion may be used for further pathological examination after routine cytology has shown negative results. At the same time, we concluded that lung cancer may easily go undetected in the patients with pulmonary amebiasis and repetitive evaluation by cytology and imaging follow-up are useful to find potential cancer.