Background: Spindle cell hepatocellular carcinoma (SpHCC) has rarely been reported, and its clinicopathologic characteristics, histogenesis, and prognosis after hepatic resection have yet to be clarified.
Methods: Fifteen cases of SpHCC, including 13 surgically resected patients and 2 autopsy cases, were studied clinicopathologically and immunohistochemically.
Results: In 13 resected patients, all except 1 were male and the serum alpha-fetoprotein (AFP) was positive in 6 (46%). Portal venous invasion and intrahepatic metastases were frequent. In an immunohistochemical analysis of 13 SpHCC tumors, cytokeratin CAM 5.2 and AFP were positive in 8 (62%) tumors and 3 (23%) tumors in both ordinary HCC and spindle cell components, respectively. The spindle cell components, but not ordinary HCC components, revealed a positive reaction for vimentin in 8 (62%) tumors, S-100 protein and HAM-56 in 3 (23%) tumors, HHF-35 in 2 (15%) tumors, and alpha-smooth muscle actin, desmin, and KP-1 in 1 (8%) tumor, respectively. p53 overexpression was found in two SpHCC tumors. The survival curve after hepatic resection in the 13 patients with SpHCC was significantly worse than that of the 371 patients with Stage II-IV ordinary HCC (P < 0.001).
Conclusions: These results suggest that SpHCC represents a sarcomatous transformation of HCC. The spindle cell components revealed an immunohistochemical expression of several markers of mesenchymal cells. In addition, poor survival after hepatic resection was documented.