PMC4361915_01
Grayscale US showed a tumor with a snowman-like appearance and a relatively clear boundary in the S6 of the liver, with hypo- and hyperechoic areas in the lateral (arrowhead) and medial parts (arrow) of the lesion, respectively (a). Contrast-enhanced CT showed a tumor prolonged enhancement in the equilibrium phases (arrow) (b). MRI showed high intensity in the lateral part of the tumor (arrowhead) and higher intensity in the medial part of the tumor (arrow) on heavy T2-weighted imaging (c).
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F1
Grayscale US showed a tumor with a snowman-like appearance and a relatively clear boundary in the S6 of the liver, with hypo- and hyperechoic areas in the lateral and medial parts of the lesion, respectively (fig. 1a). The tumor had a pale, low-density area on unenhanced CT, and prolonged enhancement in the equilibrium phases (fig. 1b). Similarly, the lateral part showed high intensity and the medial part had a higher intensity on heavy T2-weighted imaging (fig. 1c).
The lateral part of the lesion showed homogenous hyperenhancement (arrowhead) and the medial part of the lesion showed gradually stained from the margin toward the central region (arrow) in the vascular phase on contrast-enhanced US (16 s (a), 18 s (b), 20 s (c), 22 s (d) after injection).
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F2
The medial hyperechoic region was gradually stained from the margin toward the central region (fig. 2).
A cut section of the resected liver showed a whitish nodular lesion in the medial part (white arrow) and a yellowish-white nodular lesion in the lateral part (black arrowhead) (a). The medial part comprised blood vessels formed by a single layer of flattened endothelial cells and an interstitium formed by thin connective tissue. In the lateral part, lymphocyte infiltration in a dense arrangement was observed (a; HE, x40). On immunohistochemical staining, B lymphocytes expressing CD20 (b; CD20, x100) and CD79alpha (c; CD79alpha, x400) were present.
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F3
In the lateral part, lymphocyte infiltration in a dense arrangement was observed on HE staining, and most lymphocytes contained a moderately sized nucleus, but some cells contained a large nucleus and noticeable nucleolus (fig. 3a). B lymphocytes expressing CD20 and CD79alpha were present (fig. 3b, c), but bcl-2 expression in the germinal center was unclear.