Intraperitoneal ectopic infestation of parasites invading through gastrointestinal tract : CT findings

The purpose of this study was to evaluate the CT findings of parasitic ectopic infestation in the peritoneal cavity, a transitional route for parasites invading the gastrointestinal tract, to migrate to various target organs. CT scans of nine patients with pathologically(n=8) or serologically(n=1) proven intraperitoneal involvement of parasitic infestation were retrospectively reviewed. The primary causes of parasitic infestation in nine patients were Paragonimus westermani(n=5), Sparganosis(n=2), and hepatic fascioliasis(n=2). We analyzed the CT findings with regard to the sites and patterns of lesions in the peritoneal cavity and gastrointestinal track, as well as in other solid organs. The clinical features of these patients were also evaluated. The clinical symptoms and signs were chronic abdominal pain and general weakness in seven patients, while peripheral blood eosinophilia was observed in four. The CT features of these nine patients included multiseptated cystic masses of 2-6cm, diameter (mean 4.1±1.7cm) in the omentum or mesentery in six(67%), omental or mesenteric infiltration in seven(78%), focal peritoneal thickening in seven(78%), 1ymphadenopathy in five(56%), and ascites in four(44%). In six of the nine patients, the gastrointestinal tract(stomach in four, colon in one, both stomach and colon in one) was concomitantly involved with focal wall thickening. Branching patterns of hypoattenuating lesions were noted in the liver of three patients; two of these had hepatic fascioliasis and one had paragonimiasis. Ectopic parasitic infestation in the peritoneal cavity manifests as mass formation, adjacent gastrointestinal wall thickening, and focal peritonitis. An understanding of these image features is important for both early diagnosis and adequate treatment