Granulomatous Vasculitis in Cutaneous Hydrophilic Polymer Embolism.

Hydrophilic polymers are widely used as coatings on intravascular devices to reduce friction with the vessel wall, thereby minimizing vascular injury and vasospasm. However, delamination of these coatings can lead to hydrophilic polymer embolism (HPE), which may cause distal ischemia and/or inflammation. HPE can involve the brain, skin, heart, kidneys, and lungs, with clinical manifestations varying by sites. Cutaneous findings typically include livedo racemosa and purpuric macules on the lower extremities, emerging hours to days after endovascular procedures. We report a unique case of cutaneous HPE presenting with granulomatous vasculitis. An 82-year-old man presented with a fever of 38°C and painful erythematous macules on his lower limbs. He had undergone endovascular repair of an abdominal aortic aneurysm 22 days earlier. The eruption initially began on the thighs and progressed to involve the lower extremities, resulting in difficulty walking. Skin biopsy revealed angiocentric inflammatory infiltrates from the dermis to the subcutis, with suppurative granuloma formation. Non-polarizing intravascular material was identified within vessels at the dermal-subcutaneous junction, along with features of necrotizing vasculitis. Elastica van Gieson staining highlighted the intravascular materials in purple-black and demonstrated disruption of the internal elastic lamina of the arteriole and small artery. The lesions responded well to oral prednisolone (15 mg/day), which was tapered and discontinued over 2 weeks. Although similar granulomatous features have been described in other organs, to our knowledge, this is the first report of cutaneous HPE with granulomatous vasculitis. This case expands the clinicohistopathological spectrum of cutaneous HPE and alerts dermatologists to HPE as a differential diagnosis of cutaneous granulomatous vasculitis, particularly in patients following endovascular interventions. Notably, cutaneous manifestations may arise weeks after the procedure. Systemic corticosteroids may represent a potential therapeutic option in such cases.