A 63-year-old man had been followed up for chronic hepatitis C since 1998 at another medical facility. In September 2006, a tumor was found in liver segment 7 that was diagnosed as HCC. The patient was referred and admitted to our hospital. His past medical history included only hypertension. There was no family history of hepatic disease. On admission, physical examination revealed no abnormalities. Laboratory findings included: WBC 6,000/μl, RBC 488 × 104/μl, Hb 15.5 g/dl, Ht 45.9%, Plt 15.3/104/μl, T.Bil 1.3 mg/dl, albumin 4.2 g/dl, AST 49 IU/l, ALT 57 IU/l, ALP 241 IU/l, γGT 65 IU/l, PT 77%, and ICG R15 20.4%. AFP was 17.9 ng/ml, and PIVKA-II was 202 mAU/ml. Hepatitis C virus antibody was positive.
Abdominal ultrasonography and computed tomography examinations showed a solitary mass 45 mm in diameter in liver segment 7. The mass had a regular circumference, a very clear boundary, and a fibrous capsule. It showed heterogeneous enhancement in the early phase and comparatively low density in the late phase. An area with fat deposition coexisted with a hypervascular area (fig. ). T1-weighted magnetic resonance imaging (MRI) showed irregular and slightly high intensity with arterial enhancement, and nonuniform high-intensity areas with prominent fatty change. T2-weighted MRI showed a high-intensity lesion in the same area. On abdominal dynamic MRI, the tumor showed prominent fat deposition inside, and it was heterogeneous, with high intensity on T1-weighted images in the arterial phase (fig. ). Ultrasonography demonstrated that there was no vessel invasion (fig. ). These examinations suggested that the preoperative diagnosis was a relatively well-differentiated, nodular type of HCC with fatty change and a clinical stage I according to the TNM classification.
A partial resection of liver segment 7 was performed. The operative findings showed that this was HCC without metastases. The patient's postoperative course was satisfactory, and he was discharged on postoperative day 9 without complications. Currently, about 2.5 years after surgical resection, he has had no recurrence.
Macroscopically, the tumor presented as a single mass measuring 4.5 × 4.1 × 3.5 cm. The liver margin in the specimen was negative for cancer. The cut surface of the tumor was a yellow-white color, with a white part in the central area that was expansive and protruded. This showed nodular type HCC (fig. ). Microscopically, the noncancerous lesion showed infiltration of inflammatory cells and rhexis images of the limiting plate at the periportal region; this was diagnosed as active chronic hepatitis. The tumor lesion showed a moderately differentiated HCC that consisted mainly of a thick trabecular pattern, with some thin parts and other thick parts. There was also the lesion with cells with clear cytoplasm corresponding to the white lesion in the face of the cut tumor (fig. ). The white lesion contained rich fatty tissue. Despite the fact that it was a moderately differentiated adenocarcinoma, with a diameter of 45 mm, it had a fat-rich lesion [
3]. Immunohistochemical staining was performed. The lesion was mainly composed of foamy histiocyte-like cells, which were negative for CD68, S-100, vimentin, and HMB-45. Cytologically, the lesion contained medium-small fat vacuoles that were negative for PAS-ALB. The cytoplasm itself was negative on PAS and Sudan staining (fig. ). The other immunohistochemistry and histological findings are shown in table .
| Table 1Immunohistochemical findings in foamy histiocyte-like cells |
