Abstract
Unilateral calf swelling and pain is not a common complaint in the pediatric emergency department. We present a case of a 17-year-old adolescent boy with no past medical history who presented with left leg swelling and pain while taking prednisone and isotretinoin. He was found to have an extensive occlusive thrombus throughout the deep venous system in his left leg. He was later diagnosed with May-Thurner syndrome, an anatomic variant in which the right iliac artery compresses the left iliac vein. We review the differential diagnosis, diagnostic workup, and initial ED management of deep venous thrombosis and provide a brief discussion of May-Thurner syndrome and the association of isotretinoin and vascular thrombi.