Hepatocellular carcinoma in non-alcoholic fatty liver disease (NAFLD) - pathological evidence for a predominance of steatohepatitic inflammatory non-proliferative subtype.

OBJECTIVES: This study evaluated clinical and pathological aspects of patients with hepatocellular carcinoma (HCC) secondary to non-alcoholic fatty liver disease (NAFLD) and related these factors to immunohistochemical markers representative of the proliferative class. METHODS: We evaluated 35 HCC nodules from 21 patients diagnosed with NAFLD undergoing liver resection (n=12) or liver transplantation (n=8) or both (n=1). Demographic, clinical and biochemical data were compared to histological features and to immunohistochemical reactivity for K19 and Ki-67. RESULTS: Cirrhosis was present in 58% of patients. Ages ranged from 50 to 77 years. Sixteen patients (76%) were male and had type 2 diabetes mellitus, 81% had arterial hypertension, and 90% had BMI above 25 kg/m². Alpha-fetoprotein levels were normal in 62% of patients. Twenty-five (70%) nodules were diagnosed as "steatohepatitic HCC". Only 32% of the nodules presented high levels of Ki-67 (>10%) and/or K19 (>5%), although 63% were poorly differentiated (G.3/G.4) according to Edmondson & Steiner grading system. K19 positivity (>5%) was associated with higher degree of intratumoral inflammation (G.2/G.3), and with fibrosis, both at the center of the tumor and at the tumor front, whereas Ki-67 positivity (>10%) was associated with ballooning of neoplastic cells and occurred in more than 70% in non-cirrhotic patients. CONCLUSION: NAFLD-related HCC was found in non-cirrhotic patients in 42% of cases, alpha-fetoprotein level was normal in 63% and "steatohepatitic HCC" was the predominant histological type. Immunoexpression of K19 and/or Ki-67 occurred in 32% of the nodules and were associated with intratumoral inflammation and ballooning, suggesting that HCC in MtS may be preferentially "an inflammatory, non-proliferative subtype of HCC".