Fig. 1.
A 37-year-old man (case 1) presented with right flank pain. Peripheral white blood cell count was 45,100/mm3, with 94% eosinophilia.
A. Arterial phase CT scan shows a small, wedge-shaped low-attenuated lesion in the peripheral part of the posterior segment of the right hepatic lobe (white arrow). Attenuation of the right hepatic lobe is slightly lower than that of the left lobe. The diameter of the posterior branch of the portal vein (arrowheads) is less than 50% of normal. Note the right hepatic artery (black arrow). The liver is moderately enlarged.
B. CT scan at 3.5 cm cephalad to A in the portal venous phase shows low attenuation at the right hepatic lobe, with slight heterogeneity. Note the sharp border between the lesion and normal parenchyma (open arrow).
C. CT scan at the same level as A during the portal phase shows heterogeneous low attenuation in the right hepatic lobe, with a sharp straight border (open arrow). A small subsegmental low attenuated lesion was also seen in the medial segment of the left hepatic lobe (arrow). Note abrupt narrowing of the posterior branch of the right portal vein.
D. CT scan during the equilibrium phase shows a small, wedge-shaped low attenuated lesion in the right hepatic lobe (the same area as in A, open arrow) and another area of faint low attenuation (arrow). Note the significantly narrow posterior branch of the right portal vein (arrowheads).
E. Follow-up CT scan one month after corticosteroid treatment shows a subsegmental, faint zone of low-attenuation zone (open arrow) and a tiny subcapsular low attenuated lesion (arrow). Note the presence of normal portal venous branches in the posterior segment of the right hepatic lobe (arrowheads).
F. Photomicrograph of needle biopsy specimen reveals severe infiltration of the periportal area by eosinophils and mononuclear cells, resulting in widening of this area and destruction of the hepatic cell cord architecture. Note infiltration of the wall of the portal venule by eosinophils (arrows) and mononuclear cells (arrowheads), resulting in thickening of the wall as well as distortion and narrowing of the lumen (H & E, × 400).