Sarcoid Vasculitis in the Skin: A Clinicopathologic Study of 8 Cases With Various Skin Lesions but the Common Unique Cannonball-like Vessel Destruction by Sarcoid Granulomas.

While the skin is a common target organ for sarcoidosis, cutaneous granulomatous vasculitis is rare among patients with sarcoidosis. Due to the lack of detailed studies on cutaneous sarcoid vasculitis, both dermatologists and pathologists remain unfamiliar with this rare but important vasculitic disorder. We clinicopathologically evaluated eight cases with biopsy-proven cutaneous vasculitis and cutaneous sarcoidosis and analyzed morphologic changes in the process of vasculitis for both small vessels and muscular vessels in detail. The various skin lesions ranged from papulonodular erythema, annular erythema, maculopapular erythema, livedo reticularis-like eruptions, erythema nodosum-like lesions, subcutaneous nodules to ulcerative lesions. The extremities were the most frequently affected sites. Bilateral hilar lymphadenopathy with pulmonary sarcoidosis was the most common extracutaneous comorbidity. Skin-limited sarcoidosis was identified in 3 cases. All cases demonstrated a common histopathologic feature with sarcoid granulomas impinging on the target vessels with resultant vessel destruction. Perivascular infiltration of sarcoid granulomas resulted in compression and destruction of small vessels. In muscular arteries and veins, sarcoid granulomas closely attached to the muscular vessel wall, infiltrated the muscular layers and either occupied or penetrated the vessel walls, eventually invading the vascular lumen and replacing the entire muscular layers. The intimal infiltration of sarcoid granulomas resulted in a marked luminal narrowing. The scarcity of reports on cutaneous sarcoid vasculitis may be due to the overlooking or misinterpretation of vascular destruction caused by sarcoid granuloma infiltration as a feature of sarcoid granuloma masses.