Segmental mediolytic arteriopathy of the splenic and hepatic arteries mimicking systemic necrotizing vasculitis

Segmental mediolytic arteriopathy, a rare, noninflammatory arterial disease, is fundamentally a variant of fibromuscular dysplasia. The characteristic angiographic findings of segmental mediolytic arteriopathy include the "string of beads" and microaneurysms which are indistinguishable from those of vasculitis, and the correct diagnosis can be made only after histopathologic evaluation of the arterial lesions. Thrombosis, arterial wall hemorrhage, and dissection are among the complications of segmental mediolytic arteriopathy. We describe herein a patient with segmental mediolytic arteriopathy who presented with hemoperitoneum. The patient underwent urgent surgical repair of a ruptured hepatic artery aneurysm. The postoperative visceral arteriography findings led to a clinical diagnosis of polyarteritis nodosa, and immunosuppressive therapy was initiated. This treatment was stopped as soon as the correct biopsy diagnosis of segmental mediolytic arteriopathy was obtained through outside consultation. The patient recovered without drug treatment and was spared the potentially life-threatening complications of immunosuppression.