Thrombocytosis as a Rare Paraneoplastic Syndrome Occurring in Hepatocellular Carcinoma: A Case Report

Hepatocellular carcinoma (HCC) affects more than half a million people worldwide each year. Paraneoplastic syndromes associated with HCC include erythrocytosis, hypercalcemia, hypercholesterolemia, hypoglycemia and thrombocytosis. Thrombocytosis is a rare paraneoplastic syndrome in HCC mediated by thrombopoietin (TPO) production. We report a case of thrombocytosis as a paraneoplastic syndrome in a patient with HCC and hepatitis C cirrhosis. A 56-year-old patient was evaluated with abdominal distension and pain of 1-month duration. He had a history of hepatitis C infection with liver cirrhosis, CTP (Child-Turcotte-Pugh) class C, MELD (model for end-stage liver disease) score 22, methadone dependence, alcohol abuse and depression. His physical examination was remarkable for distended abdomen with shifting dullness, palpable hepatomegaly and scleral icterus. Routine laboratory tests showed a platelet count of 754 k/µL, white blood cell count 12.4 k/µL, serum sodium level 128 mEq/L, alanine aminotransferase 93 U/L, aspartate aminotransferase 871 U/L, total serum bilirubin 4.3 mg/dL, direct serum bilirubin 2.8mg/dL and albumin 2.6 g/dL. Computed tomography of the abdomen and pelvis revealed hepatomegaly with numerous hypodensities suspicious for HCC. Abdominal paracentesis was done, serum ascites albumin gradient (SAAG) was 2.4 g/dL consistent with portal hypertension, and spontaneous bacterial peritonitis was ruled out. Magnetic resonance imaging of the liver was consistent with infiltrating HCC, portal vein thrombosis and retroperitoneal lymphadenopathy. His alpha fetoprotein (AFP) level was 79,102 ng/mL and TPO level was 126 pg/mL. JAK2 mutation was negative and no other cause of reactive thrombocytosis could be identified. One year prior to this admission, the patient was noted to have a normal platelet count and AFP level. He was not considered a candidate for liver transplantation due to ongoing substance abuse, and expired 1 month later. Thrombocytosis is a rare paraneoplastic condition seen in HCC. It is presumed to be secondary to increased production of TPO by the tumor. We observed an elevated level of TPO in our patient. Thrombocytosis in HCC is associated with a high tumor burden, portal vein thrombosis (PVT), serum AFP levels and a poor prognosis. Thrombocytosis in a cirrhotic patient should alert the presence of HCC and is associated with poor outcomes.