Published online Aug 7, 2020. doi: 10.3748/wjg.v26.i29.4327
Peer-review started: March 11, 2020
First decision: April 8, 2020
Revised: April 24, 2020
Accepted: July 14, 2020
Article in press: July 14, 2020
Published online: August 7, 2020
Hepatocellular carcinoma (HCC) is the sixth most common type of cancer and the fourth leading cause of cancer-related death worldwide. Sarcomatoid HCC, which contains poorly differentiated carcinomatous and sarcomatous components, is a rare histological subtype of HCC that differs from conventional HCC. It is highly aggressive and has a poor prognosis. Its clinicopathological characteristics, surgical outcomes and underlying mechanisms of its highly aggressive nature have not been fully elucidated.
To examine the clinicopathological characteristics and surgical outcomes of sarcomatoid HCC and explore the histogenesis of sarcomatoid HCC.
In total, 196 patients [41 sarcomatoid HCC and 155 high-grade (Edmondson-Steiner grade III or IV) HCC] who underwent surgical resection between 2007 and 2017 were retrospectively reviewed. The characteristics and surgical outcomes of sarcomatoid HCC were compared with those of patients with high-grade HCC. The histological composition of invasive and metastatic sarcomatoid HCCs was evaluated.
Sarcomatoid HCC was more frequently diagnosed at an advanced stage with a larger tumor and higher rates of nonspecific symptom, adjacent organ invasion and lymph node metastasis than high-grade HCC (all P < 0.05). Compared with high-grade HCC patients, sarcomatoid HCC patients are less likely to have typical dynamic imaging features of HCC (44.4% vs 72.7%, P = 0.001) and elevated serum alpha-fetoprotein levels (> 20 ng/mL; 36.6% vs 78.7%, P < 0.001). The sarcomatoid group had a significantly shorter median recurrence-free survival (5.6 mo vs 16.4 mo, log-rank P < 0.0001) and overall survival (10.5 mo vs 48.1 mo, log-rank P < 0.0001) than the high-grade group. After controlling for confounding factors, the sarcomatoid subtype was identified as an independent predictor of poor prognosis. Pathological analyses indicated that invasive and metastatic lesions were mainly composed of carcinomatous components.
Sarcomatoid HCC was associated with a more advanced stage, atypical dynamic imaging, lower serum alpha-fetoprotein levels and a worse prognosis. The highly aggressive nature of sarcomatoid HCC is perhaps mediated by carcinomatous components.
Core tip: Sarcomatoid hepatocellular carcinoma is a rare malignancy. Patients usually present with an advanced stage of the disease and have a poor prognosis. Histopathological examination plays an important role in diagnosis because serologic and radiologic examinations cannot help in distinguishing this disease from conventional hepatocellular carcinoma or other intrahepatic masses. Most patients have a history of chronic liver disease; thus, regular ultrasound screening of such patients can help detect tumors at an early stage and reduce the risk of death. Moreover, we discovered that carcinomatous components occupied the predominant proportion of invasions and metastases, and we developed a hypothesis regarding the occurrence of the disease.