Clinicopathological study of scirrhous hepatocellular carcinoma

BACKGROUND AND AIMS: Scirrhous hepatocellular carcinoma (SHCC) is characterized by diffuse fibrosis of the tumor, however, its clinicopathological features are not fully clarified. This study aimed to clarify the clinicopathological features of SHCC. METHODS: Among 546 consecutively resected HCC without preoperative anticancer therapies, 25 SHCC were selected for the study and compared with 521 cases without scirrhous as the control. RESULTS: SHCC accounted for 4.6% of cases. On diagnostic imagings, SHCC was frequently misdiagnosed as cholangiocarcinoma (CC), combined HCC-CC or metastatic carcinoma. Overall survival rate was significantly higher than the control. The average (+/-SD) tumor size of SHCC was 3.4 +/- 1.8 cm without significant difference to the control. The majority of SHCC (88%) were located close to the liver capsule. SHCC was characterized by stellate fibrosis (84%), no encapsulation (100%), no necrosis and hemorrhage (100%), intratumoral portal tracts (80%), remarkable lymphocyte infiltration (84%), clear cell change (84%), and hyaline bodies (52%). The number of alpha-smooth muscle actin-positive myofibroblast-like cells (activated stellate cells) in the tumor was about three times more than that in the control. Regarding the developmental mechanism of scirrhous change, a close correlation with unique tumor location and activation of stellate cells was suggested. CONCLUSIONS: SHCC presents with characteristic clinicopathological features and the recognition of SHCC is important for both clinicians and pathologists.