Fig. 2.

A 71-year-old male hepatitis B virus carrier with hepatocellular carcinoma exhibiting irregular rim-like enhancement (IRE-HCC). A 5.5-cm tumor in the right superior hepatic section shows low-signal intensity on precontrast T1-weighted imaging (a) as well as IRE in the arterial phase (b) of gadoxetate-enhanced MRI. Tumor necrosis is more prominent in the central portion of HCC (hatched in black) (c, hematoxylin-eosin [H-E] stain), and fibrous tumor stroma is marked by a red color (d, Sirius red stain). The tumor mainly comprises a macrotrabecular pattern (e, H-E stain). A sinusoid-like microvascular pattern is noted with low microvascular density as 177/mm² on immunostaining for CD34 (f), K19 (g) and EpCAM (h) are not expressed, while positive expression of carbonic anhydrase IX (CAIX) is noted (i). Original magnification, ×100.