Leech endoparasitism: report of a case and review of the literature.

We report the case of an 11-year-old boy who presented with fresh blood in his mouth and a history of sore throat during the past 2 weeks that was unresponsive to antibiotic therapy. Inspection of the oral cavity revealed a black circular mass attached to the posterior wall of the oropharynx. This mass was determined to be a live engorged leech. Leech endoparasitism is caused by aquatic leeches that attach themselves to mucus membranes of body cavities after the host has swum in bodies of fresh water or drunk from unsafe water sources. Pharyngeal hirudiniasis may present in different forms depending on the exact location of the parasite in the body and must be included in the list of differential diagnosis for common conditions such as pharyngitis, hemoptysis or anemia in pediatric patients living in endemic areas.