Although amebic brain abscess is a rare form of invasive amebiasis, when present, it is frequently lethal. This disorder always begins with the infection of the colon by Entamoeba histolytica trophozoites, which then travel to extra-intestinal tissues through the bloodstream. Amebic brain abscesses are produced when trophozoites invade the central nervous system. Computerized axial tomography scans can be used to diagnose the presence or absence of a brain abscess with a certainty of 100%. However, this diagnostic tool does not reveal the etiological agent of disease. By analyzing the clinical case of a patient that died due to untimely treatment of this malady, the present study aims to identify a diagnostic tool that can give a precise determination of the etiological agent and therefore permit adequate and opportune treatment. Currently, diagnosis of amebic brain abscess is often done by identification of the ameba in a biopsy or autopsy. By immunohistochemistry and immunofluorescence with specific antibodies, we identified the existence of E. histolytica, which presents proteins similar to Naegleria fowleri in its membrane.