Pelvic deep venous thrombosis mimicking lower limb cellulitis in systemic lupus erythematosus-associated antiphospholipid syndrome

Objectives: Systemic lupus erythematosus (SLE) associated with antiphospholipid syndrome (APS) is a complex clinical scenario with thromboembolic events, lupus activity, and related therapeutic complications like infection. In SLE, iliofemoral (IF) deep vein thrombosis (DVT) with fever and erythematous swollen limbs mimic cellulitis over lower extremities. Nevertheless, to distinguish DVT from cellulitis is imperative in clinical practice due to the use of different therapeutic regimens. Methods: A retrospective study was performed to analyze iliofemoral DVT in hospitalized SLE-associated APS patients with fever and erythematous swollen limbs mimicking cellulitis from January 1, 2011 to December 31, 2020. Results: Among 896 hospitalized SLE patients, 117 were associated with APS. Three patients had pelvic IF DVT with total vascular occlusion, presenting as fever and erythematous swollen limbs mimicking cellulitis. Despite negative duplex sonographic findings, IF thrombi were demonstrated by using computed tomography and/or catheter venography. Owing to refractory to unfractionated or low-molecular-weight heparin injection, all received the thrombolytic treatment. Complete resolution of thrombi without recurrent DVT and post-thrombotic syndrome was identified in two patients receiving pharmacomechanical thrombectomy or catheter-directed thrombolysis. Conclusions: For differential diagnosis of IF DVT and lower limb cellulitis in SLE-associated APS, our case series underlines the importance of venography to detect an unusual pelvic location of thrombi.