Asymptomatic amebic colitis in a homosexual man.

We describe case of a 75-yr-old Japanese homosexual man who was diagnosed as having amebic colitis. The present case is unique in that invasive amebiasis has occurred in a homosexual man, because Entamoeba histolytica in homosexual patients is considered to be a nonpathogenic and commensal organism in western countries, and that the patient has not complained of any gastrointestinal symptoms associated with minute colonic lesion of an isolated cecal ulcer. This report indicates that the absence of gastrointestinal symptoms does not rule out invasive amebiasis. Therefore, once the ameba is identified in stool specimens, even in homosexual men, it is important to differentiate pathogenic from nonpathogenic species irrespective of whether the patient is symptomatic, and to treat the patient infected with pathogenic species. By means of this strategy, we can prevent pathogenic ameba from spreading in the community.