Cystic Arterial Disease Localized in the Media of the Popliteal Artery With Dissection.

Adventitial cystic disease (ACD) of the popliteal artery is a rare disease that can cause intermittent claudication, and most cases show cysts located in the adventitia. We report a rare case with a cyst localized in the media and a dissection. The patient presented to the hospital with sudden-onset right lower limb pain. A lower limb ultrasound revealed an iso-echoic lesion in the right popliteal artery, leading to an initial diagnosis of thrombotic occlusion and subsequent thrombectomy. However, intravascular ultrasound suggested the lesion was outside the intima, and magnetic resonance imaging findings indicated ACD. Consequently, cyst resection with expanded polytetrafluoroethylene (ePTFE) graft reconstruction was performed. Histopathological examination revealed dissection associated with cystic medial necrosis. However, the condition was diagnosed as cystic arterial disease due to its similarity to previously reported cases and the inadequacy of the term "adventitial" cystic disease.