Tehran University of Medical Sciences Case Reports in Clinical Practice 2538-2683 6 1 2021 05 15 11 14 Morteza Daraei Department of Internal Medicine, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran. Sahar Karimpour Reyhan Department of Internal Medicine, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran. Mahsa Abbaszadeh Department of Internal Medicine, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran. Ali Afshari Department of Internal Medicine, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran. 2020 04 01 2020 05 05 Systemic Lupus Erythematous (SLE) is a chronic autoimmune disorder with a relapsing- remitting course. Besides, SLE most commonly occurs in child-bearing-age women. Due to protean manifestations, the diagnosis may be challenging; however, a high index of suspicion, i.e. achieved by experience and perceptivity is the key to a correct decision. Here, we present an SLE patient; her initial symptoms resembled a malignant process, but important elements guided us to the underlying autoimmune process. A 34-year-old woman presented with a uterine mass, deep vein thrombosis, and significant thrombocytopenia. Our first impression was malignant processes; however, considering her age with thrombosis and thrombocytopenia as the key components of her presentation, we suspected antiphospholipid syndrome and SLE. Her abdominal mass was a benign leiomyoma. We treated her with glucocorticoids and anticoagulants. Accordingly, after improving cytopenia, we discharged her and the follow-up examination result was satisfactory. https://crcp.tums.ac.ir/index.php/crcp/article/view/348 https://crcp.tums.ac.ir/index.php/crcp/article/download/348/390