Portal vein thrombosis due to essential thrombocythemia with limited cutaneous systemic sclerosis.

Portal vein thrombosis is caused by various diseases, including liver cirrhosis, cancer, abdominal infection, and myeloproliferative disorders. Essential thrombocythemia is one of the myeloproliferative disorders in which the bone marrow produces excessive amount of platelets and can be accompanied by various thrombotic diseases; however, essential thrombocythemia with limited cutaneous systemic sclerosis has not been reported yet. We herein report a case of extensive portal vein thrombosis due to essential thrombocythemia with limited cutaneous systemic sclerosis. A 49-year-old woman was referred to our hospital due to liver dysfunction. Extended portal vein thrombosis, splenomegaly, and thrombocytosis were founded. The examination of Janus kinase 2 V617F mutation in the bone marrow was positive. These findings resulted in the diagnosis of portal vein thrombosis due to essential thrombocythemia. Furthermore, Raynaud's phenomenon, finger's sclerosis, and positive anti-centromere antibody led to limited cutaneous systemic sclerosis. To further analyze the causal relationship between essential thrombocythemia and limited cutaneous systemic sclerosis, platelet-derived growth factor was examined. High level of serum platelet-derived growth factor, possibly caused by high platelet count due to essential thrombocythemia, was observed. As platelet-derived growth factor has been reportedly associated with the occurrence of systemic sclerosis, the present case indicates the possible causal link between essential thrombocythemia and limited cutaneous systemic sclerosis through high platelet-derived growth factor.