In the WHO-HAEM4, HAEM5 and ICC the diagnosis of IgM monoclonal gammopathy of undetermined significance (MGUS) is made in cases showing <10% of BM neoplastic cells with lymphoplasmacytoid or plasma cell differentiation without lymphoplasmacytic B-cell aggregates diagnostic of LPL [42]. Here, CD40LG is linked to intrahepatic cholangiocarcinoma.