Introduction: Hepatocellular carcinoma (HCC) is the most common primary malignant tumor in the liver. It is three times more common in men than in women. Several typical histologic patterns of hepatocellular carcinoma have been described by the World Health Organization; the most common is the trabecular pattern. We present a rare case of HCC with prominent fatty change that metastasis to lung 10 months after liver transplantation.

Case Report: We report the case of 57-year-old woman who received a right lateral segment liver transplant from his daughter who was 25 years old and started to use tacrolimus and mikofenolat mefotil based immunosuppression regimen. The patient has been reviewed because of elevated serum hepatitis B surface antigen (HBsAg) for 17 years and has chronic liver disease symptoms for two years. She has been followed by another hospital. Multipl solid nodules in liver has been recognized in routine control and the biopsy of this nodule was reported as HCC. She underwent arterial chemoembolization in two times for HCC. Then she was referred to Başkent University for liver transplantation. In the histopathologic examination of nativ liver, HCC with necrosis depending on chemoembolization and cirrhosis were noted. Fatty change was only focal in tumor cells.Ten months after transplantation, she was presented with persistant cough and computed tomograpy of the chest revealed a solid lung mass in her right inferior lobe and lobectomy was performed. In the histopathological examination of lobectomy, HCC with prominent fatty changes was detected.

Conclusions: HCC with prominent fatty change is extremely rare and the histological picture is different from the usual HCC, so it may cause some diagnostic difficulties especially in metastatic lesions. In metastasis to lung, fat droplets in the tumor cell cytoplasm may confused with the accumulation of aspirated oils in lipoid pneomonia, especially in small needle biopsies. We presented this case because of its rarity and having some difficulties in differential diagnosis in liver transplant recipients.