Ultrasonographic diagnosis of schistosomal periportal fibrosis.

Hepatosplenic schistosomiasis results from infestation by Schistosoma mansoni, a blood fluke. Presinusoidal periportal fibrosis is invariably the result of this infestation. The ultrasonic pattern of schistosomal periportal fibrosis in 22 patients in whom schistosomal hepatic involvement was proven histologically is described. Echogenic areas of pipestem fibrosis seen as tubular shadows, some containing central lucencies, were present in every case. These tubular shadows conformed to the structure of the portal veins, producing a characteristic appearance. In endemic areas this appearance may be the only clue to the diagnosis of hepatosplenic schistosomiasis, because patients may remain asymptomatic for years after the onset of the disease.