Histological subtypes of hepatocellular carcinoma: Their clinical and prognostic significance.

Assigning a hepatocellular carcinoma (HCC) to an appropriate subtype is important because this guarantees the diagnosis and treatment and allows decisions regarding the prognosis of the patient. HCC subtyping is usually based on the World Health Organization (WHO) classification and the 2019 fifth edition is the latest version. However, the WHO classification system is still in evolution and has limited clinical relevance. We aimed to evaluate the clinical relevance of HCC subtyping and to reappraise some of the major subtypes of HCC. Our archived cases (n = 589) were reclassified according to the 2019 WHO system. The percentage of each subtype was mostly similar to that in the WHO classification. However, on the contrary to the 2019 WHO system, clear cell type HCC was associated with more frequent recurrence or metastasis. Meanwhile, macrotrabecular massive HCC was related to poor prognosis as demonstrated in the 2019 WHO system and should be described in the pathology report. For steatohepatitic HCC, there is a debate on whether it is a true subtype because the steatohepatitis morphology may or may not be present in the background liver. In our study, 44 % of steatohepatitic HCCs (n = 19/43) presented underlying steatohepatitis. Additionally, the background cirrhosis did not influence survival in the HCC patients, although the 2019 WHO system indicates the presence of cirrhosis as a poor prognostic factor. In conclusion, although it is not perfect yet, HCC subtyping based on the 2019 WHO system provides valuable information to manage patients with HCC. • Clinical relevance of HCC subtyping was clarified with the 2019 WHO classification. • Clear cell type HCC was associated with more frequent recurrence or metastasis than the NOS type. • Macrotrabecular massive HCC was related to poor prognosis and should be described in the pathology report. [ABSTRACT FROM AUTHOR]