Steatohepatitic hepatocellular carcinoma: morphological diagnostic criteria and clinicopathological characteristics

Abstract According to the WHO, steatohepatitic hepatocellular carcinoma (SH-HCC) is a distinct HCC subtype. Its prevalence and prognosis vary depending on the study, probably because of lack of a consensus pathological definition. The objectives of the study were to carefully describe the morphological features of SH-HCC to propose a relevant pathological definition and evaluate its impact on prognosis. We conducted a single-centre retrospective study including 297 surgically resected HCC. Pathological features of the tumor including SH criteria (steatosis, ballooning, Mallory-Denk bodies, fibrosis, and inflammation) were assessed. The diagnosis of SH-HCC was initially based upon the presence of at least 4 of the 5 SH criteria and the SH component represented > 50% of the tumor area. According to this definition, a total of 39 (13%) HCC cases corresponded to SH-HCC and 30 cases (10%) corresponded to HCC with SH component (< 50%). SH criteria were distributed as follows: ballooning :100% in SH-HCC vs 11% in non–SH-HCC, fibrosis:100% vs 81%, inflammation:100% vs 67%, steatosis :92% vs 8%, and Mallory-Denk bodies :74% vs 3%. Five-year recurrence-free survival (RFS) and 5-year overall survival (OS) were similar for SH-HCC and non–SH-HCC cases (p = 0.413; and p = 0.866, respectively). The percentage of SH component does not impact OS and DFS (p = 0.589; and p = 0.443). Based on these results, we propose a simplified definition of SH-HCC based on ballooning as a major criterion with at least 2 other SH criteria regardless the extent of SH component. Eighty-three HCC (28%) corresponded to SH-HCC according to this definition, including all HCC classified initially as SH-HCC and HCC NOS with SH contingent. Finally, we confirm in a large cohort the high prevalence of SH-HCC and propose a simplified SH-HCC definition that could be easily applied in routine practice.