Concentric Rings: Updated CT Appearance of Hepatic Schistosomiasis Mansoni

Schistosomiasis is an infectious disease affecting up to 300 million people worldwide [1]. Of the three main species of Schistosoma, S. mansoni has the broadest geographical distribution. It is endemic to portions of South America, sub-Saharan Africa, the Middle East, and the Caribbean. S. haematobium is found mostly in North Africa, parts of sub-Saharan Africa, and the Middle East; S. japonicum is endemic to Asia. Schistosomiasis presents with different manifestations depending on the offending organism. S. mansoni and japonicum tend to affect the intestines and the liver, S. haemotobium the kidneys and bladder [2]. It is worth noting that most patients infected with schistosomiasis, particularly those from endemic regions, remain asymptomatic and the diagnosis is thus based on imaging and other laboratory studies [3]. Booming industries such as rural tourism have also contributed to the rising incidence of schistosomiasis in non-endemic regions [3,4]. CT findings of S. mansoni hepatic involvement have not been extensively published; most series of case reports date back more than ten years. To our knowledge, multi-detector CT (MDCT) images have not been published. We present a case of hepatosplenic S. mansoni infection that demonstrates a concentric ring pattern of periportal fibrosis previously described by ultrasound, but below the resolution of prior CT imaging. We show thickening and nodular changes in the gallbladder wall that may represent S. mansoni involvement of the gallbladder, a rare finding. We also present a brief updated review of the past twenty years in imaging of schistosomiasis.