PMC3033353_01
Unenhanced CT scan showed low density area of 1 cm in diameter in the segment 3 of the liver (arrow). Contrast-enhanced CT scan during arterial phase showed minimally peripheral ring enhancement. No lymphadenopathy or hepatosplenomegaly was observed.
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F1
On abdominal computed tomography (CT) scan (Figure 1), 15-mm-diameter low density area was demonstrated before contrast material injection, which was enhanced in early arterial phase and subsequently washed out in the late phase after contrast material injection, not incompatible with HCC.
Magnetic resonance imaging (MRI), the hepatic tumor (arrow) was low signal intensity in T1-weighted image (A) and slight high signal intensity in T2-weighted image (B), and low signal intensity in hepatobiliary phase after Gd-EOB-DTPA injection, and on dynamic Gd-EOB-DTPA MRI protocol not clearly visualized during arterial dominant phase with slight ring-like enhancement persisting, indicating hypovascular tumor, such as cholangiocarcinoma or liver metastasis.
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F2
FDG-PET CT demonstrated the tumor had a high standardized uptake value (SUVmax: 3.6) for FDG. No other site showed FDG uptake, suggesting that liver tumor is not secondary from malignant lesions of other organs.
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F3
In a fluorodeoxyglucose-positron emission tomography examination integrated with computed tomography scanning (FDG-PET CT, Figure 3), the tumor was revealed to have a high standardized uptake value (SUVmax: 3.6) for FDG.
Resected specimen: section of the liver and 12 x 10 mm, well-defined, light-tan, firm, solid nodule (arrow).
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F4
On macroscopic examination, there was a grey-white solid tumor, measuring 1.0 cm in largest diameter (Figure 4).
Microscopic appearance of the lesion. (A) Low-power view of the tumor showing dense lymphocytic infiltration with lymph follicles (hematoxylin and eosin, original magnification x4). (B) Interfollicular areas are infiltrated with small to intermediate-sized lymphocytes with pale cytoplasm, which are characteristic features of hepatic pseudolymphoma as well as marginal zone B-cell lymphoma (hematoxylin and eosin, original magnification x40). (C) Intermediate-sized atypical lymphocytes are observed (hematoxylin and eosin, original magnification x40). (D) Most of the lymphoid cells are positive for CD20. These cells are negative for CD5, which rules out other small B-cell non Hodgkin lymphomas, including lymphocytic lymphoma and mantle cell lymphoma (original magnification x4). (E) Bcl-2 expression in the mantle zones and the interfollicular areas (original magnification x4). (F) Lymphoepithelial lesions are observed at the bile ducts (hematoxylin and eosin, original magnification x40). (G) At the edge of the nodule, lymphocytic infiltration extends into perinodular portal tracts (hematoxylin and eosin, original magnification x10). (H) Bile ducts are observed at the periphery of the nodule (hematoxylin and eosin, original magnification x10).
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F5
On microscopic examination, the tumor in the liver was composed of dense lymphocytic infiltration including multiple lymphoid follicles with germinal centers (Figure 5A). The interfollicular areas were expanded and filled with small to medium-sized lymphocytes with pale cytoplasm and cellular atypia (Figure 5B, C), most of which were positive for CD20 and bcl-2 (Figure 5D, E), and negative for CD5 and CD10. Lymphoepithelial lesions with bile duct epithelium destruction by lymphoid tumor cells were noticed (Figure 5F). At the edge of the nodule, lymphocytic infiltration extended into perinodular portal tracts (Figure 5G). Bile ducts were observed at the periphery of the nodule (Figure 5H).