Steatotic hepatocellular carcinoma: a variant associated with metabolic factors and late tumour relapse

Steatosis in hepatocellular carcinoma (HCC) has been recognized for decades and found most commonly in small, well-differentiated HCC. However, the clinicopathological features and pathogenesis of HCC with steatosis is not well characterized. There are few data concerning whether HCC with steatosis should be regarded a distinct histological variant, steatotic HCC.

A retrospective cohort of 516 patients undergoing curative surgery for primary HCC was recruited. The median follow-up was 45.5 (range: 0.2-166.0) months. Steatotic HCC was defined as HCC with significant steatosis (≥5% of tumour cells). Associations with immunohistochemical expression of fatty acid binding protein-1 (FABP1), sonic hedgehog (SHH) and gene polymorphism of patatin-like phospholipase 3 (PNPLA3) were analysed. Steatotic HCC was found in 21.1% of patients and was associated with higher metabolic risks [diabetes mellitus (36.7% versus 18.2%) and hypertension (44.0% versus 28.7%)], underlying fatty liver (60.6% versus 37.8%), steatohepatitis (30.3% versus 13.0%), smaller tumour size, lower frequency of major vessel (1.8% versus 11.3%) and microvascular invasion (20.2% versus 32.4%), earlier tumour stages and lower serum alpha-fetoprotein. It was associated with developing late tumour relapse (hazard ratio 2.15, P = 0.002) independently of underlying cirrhosis and non-anatomical excision. Steatotic HCC did not differ from HCC without significant steatosis in immunohistochemical expression of FABP1 and SHH and PNPLA3 gene polymorphism.

Steatotic HCC is a common histological variant of HCC with distinct association with underlying fatty liver, steatohepatitis and metabolic risks. Despite more favourable baseline tumour features, it was associated with late tumour relapse.