[A case of diphyllobothriasis: description and diagnosis].

We describe a case of asymptomatic infection caused by Diphyllobothrium latum, probably following a meal of "sushi" in a Japanese restaurant in Rome one year before. The diagnosis was obtained observing morphology and seizures of proglottids and ova. We recall the life cycle of this cestode and report criteria for a differential diagnosis with other species of the Diphyllobothrium genus, usually rare in humans, and caused by the ingestion of marine fish and not freshwater fish.