Systemic lupus erythematosus and extreme thrombocytosis without autosplenectomy

Systemic Lupus Erythematosus (SLE) is an autoimmune disorder characterized by multiorgan system involvement. Hematologic manifestations are common in SLE and include thrombocytopenia in as many as 50% of patients. Thrombocytosis is much less common in SLE, occurring in less than 5% of patients, and is typically reported in association with autosplenectomy. The following case report describes a 35-year-old female patient who presented for evaluation with extreme thrombocytosis of unclear etiology. The patient was diagnosed with reactive thrombocytosis due to active SLE for which treatment with corticosteroids and plaquenil was provided with subsequent decline in platelet counts. This report highlights the importance of considering SLE in the differential for thrombocytosis despite its classic association with thrombocytopenia.