Portal hepatic lymphadenopathy involved by Rosai-Dorfman disease-like changes in a patient with hepatocellular carcinoma

We report a case of a 68-year-old woman with chronic hepatitis C who presented with a small hepatocellular carcinoma in segment 8 (S8) of liver and a portal hepatic tumor. Transhepatic arterial infusion therapy was performed, followed by partial hepatic resection of S8 and excision of the portal hepatic tumor with lymph node metastasis. Histologically, the lymph nodes showed marked infiltration of large histiocytes with clear cytoplasm and emperipolesis in the specimen stained with hematoxylin-eosin. These findings were generally compatible with the histological features of Rosai-Dorfman disease (RDD). However, immunohistochemical analysis revealed the proliferating histiocytes were negative for CD1a, CD68 and S-100 protein, but positive for only lysozyme. Therefore, we finally diagnosed it as a disease similar to RDD. This was a difficult case diagnostically distinguish between metastasis and benign disease.