A Rare Large-Artery Complication of Cryoglobulinemia

BACKGROUND: Cryoglobulinemia is an immune complex-mediated vasculitis that predominantly affects small and medium-sized vessels. Involvement of large arteries is exceedingly rare, and pseudoaneurysm formation has rarely been described. CASE SUMMARY: A 44-year-old man with hepatitis C-negative cryoglobulinemic vasculitis and a mechanical aortic valve on chronic anticoagulation presented with acute left gluteal pain, near syncope, and severe anemia. Computed tomography angiography revealed a large left gluteal hematoma with active arterial extravasation. Digital subtraction angiography demonstrated a markedly enlarged superior gluteal artery supplying a large pseudoaneurysm. Distal-to-proximal endovascular embolization resulted in complete exclusion of the pseudoaneurysm and hemodynamic stabilization. DISCUSSION: This case illustrates an exceptionally rare large-artery complication of cryoglobulinemia, highlighting the potential for immune-mediated vascular injury to extend beyond the small- and medium-vessel circulation. The deep anatomic location of the superior gluteal artery can obscure early diagnosis, and delayed recognition may result in life-threatening hemorrhage. CONCLUSIONS: Clinicians should consider vasculitic etiologies, including cryoglobulinemia, in patients presenting with spontaneous pseudoaneurysm formation and acute hemorrhage in the absence of trauma. Early recognition and endovascular intervention can be lifesaving.