title: The paradoxical halo sign in hepatic pseudotumor.
abstract: The "halo sign" in hepatic angiography is considered a reliable sign of an intrahepatic mass. A large retroperitoneal mass may present as an hepatic tumor clinically; two such cases are presented in which the halo sign was demonstrated by hepatic angiography. When this "paradoxical" halo sign is present, several factors contribute to the diagnosis of an extra-hepatic mass: (a) minimal stretching or displacement of the hepatic artery or portal vein; (b) lack of draping of the hepatic arteries around the mass; and (c) identification of abnormal vessels or a mass in an adjacent organ.
mesh_terms: D000328:Adult; D000368:Aged; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging; D001027:Aortography; D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D005260:Female; D006499:Hepatic Artery / Q000000981:diagnostic imaging*; D006801:Humans; D008113:Liver Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging*