Extreme Thrombocytosis Presenting in Anti-Neutrophil Cytoplasmic Autoantibodies-Associated Crescentic Glomerulonephritis with Immune Complex Deposits: A Case Report

INTRODUCTION: We describe a female patient with extreme reactive thrombocytosis (RT) in anti-neutrophil cytoplasmic autoantibodies (ANCA)-associated crescentic glomerulonephritis (CGN) with immune complex deposits, which has never been reported before. CASE PRESENTATION: A female adolescent with symptoms of oliguria and gross hematuresis had serious renal function impairment (crescent formation and immune complex deposits in renal pathology examination with positive serum ANCA) and extreme thrombocytosis. We made a diagnosis of CGN and RT. After treatment with Prednisone, Cyclophosphamide, and plasmapheresis, the symptoms of oliguria and gross hematuresis were relieved remarkably and the serum creatinine and platelet count declined significantly. CONCLUSIONS: The diagnosis of thrombocytosis is not easy in all cases. The coexistence of ANCA and the immune complex in CGN may cause a severe inflammatory state, leading to extreme RT. The roles that the immune complex and ANCA play on the effect of the platelet count and function in CGN need further research.