[Vasculitides: classification, clinical aspects and pathology. A review]

Imaging of primary and secondary inflammatory diseases involving large and medium-sized vessels and their potential mimics: a multitechnique approach

OBJECTIVE

The purpose of this article is to illustrate multitechnique imaging findings in patients with primary and secondary vasculitides involving large and medium-sized vessels and their mimics.

CONCLUSION

Large and medium-sized vessels are affected by many primary and secondary inflammatory disorders or mimicking conditions, often presenting similar imaging characteristics. Knowledge of distinctive imaging features such as location, length, and degree of vessel wall enhancement as well as the particular clinical settings will help the clinician in appropriately narrowing down the differential diagnosis.

[Vasculopathy in Sjögren's syndrome]

Sjögren's syndrome is a systemic autoimmune disease with a predominant involvement of exocrine glands leading to sicca symptoms. Extraglandular involvement occurs in about 40% of patients with skin, musculoskeletal, neurological and organ manifestations. Systemic vasculitic manifestations of Sjögren's syndrome can be assumed in approximately 5%-10% of patients. Leukocytoclastic or cryoglobulinemic vasculitis represent classic vasculitic manifestations of Sjögren's syndrome. In the pathogenesis of vasculitis, B-cell-driven autoimmune processes play a major role by producing autoantibodies against the Ro/SS-A and La/SS-B antigens and cryoglobulins. In patients with Sjögren's syndrome, manifestation of vasculitis, non-Hodgkin's lymphoma and glomerulonephritis, as well as positive cryoglobulins and decreased levels of complement factors, are considered negative prognostic markers. Various immunosuppressive strategies, usually in co-medication with glucocorticoids, are used for the treatment of vasculitis in Sjögren's syndrome. For refractory and severe manifestations, a B-cell-targeted therapy with Rituximab should be also considered.

[Histology of cutaneous vasculitides]

Identification of vasculitis by skin biopsy represents the diagnostic gold standard. Skin biopsies should be taken from fresh lesions or from margin of an ulceration and should contain all layers of the skin including subcutis. Classification of vasculitis is based on histological criteria considering the size of the predominantly affected vessel, the distribution of vasculitis in the dermis and subcutis, and the predominant inflammatory cell-type. In cutaneous vasculitis, small and medium-sized vessels of the arterial and/or venous system are predominant affected. Vasculitis of the larger-sized blood vessels is based on inflammatory cells within the wall of the vessel; in small vessel vasculitis, additional features include fibrin within the vessel wall and/or an intraluminal thrombus and/or perivascular and interstitial infiltrates of neutrophils, nuclear dust and extravasated erythrocytes are required for the diagnosis of vasculitis. Leukocytoclastic vasculitis is the most common form of cutaneous vasculitis. An correct diagnosis requires careful correlation of medical history, the clinical, serological, imaging and direct immunofluorescence data, and histologic findings.