ABSTRACT
Anisakis pathology is due mainly to two mechanisms: allergic reactions (from isolated urticaria and angioedema to life-threatening anaphylactic shock associated with gastrointestinal symptoms or 'gastroallergic anisakiasis'), and direct tissue damage, due to invasion of the gut wall, development of eosinophilic granuloma, or perforation (gastric or intestinal anisakiasis). Anisakiasis is a misdiagnosed and underestimated cause of acute abdomen: most patients undergo laparotomy, and virtually no cases are diagnosed before surgery. In some cases, diagnosis is obtained accidentally during other pathologic investigations. We report a case of acute abdomen due to terminal ileum involvement. Microscopic examination of the resected segment showed the presence of helminthic sections consistent with larvae of Anisakis spp. A history of raw fish ingestion was recorded. Histopathologic features are illustrated. A short but up-to-date review of the literature on diagnostic devices (particularly imaging and serology), clinical aspects and therapy is presented.