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Background
Nodular vasculitis may be two diseases. The non-tuberculosis type is known as the Whitfield type while the tuberculosis associated cases are known as Bazin type. The Whitfield type is presents with painful nodules that occasionally ulcerate, on the lower extremities, usually calves, of young to middle aged women. Resolution after several weeks is the usual course but recurrences may occur.
Histopathologically, there is a lobular panniculitis with fat necrosis, although less pronounced than in the Bazin type. Arteries and veins in the septa may show endothelial swelling and occasionally a necrotizing vasculitis, mimicking polyarteritis nodosa. Usually the small and medium sized arteries are involved in this nodular vasculitis while the larger arteries are favored in polyarteritis nodosa. In addition, the panniculitis in nodular vasculitis usually involves contiguous nodules. Inflammatory cells include neutrophils, eosinophils, histiocytes, lymphocytes, and plasma cells. Lipophages, giant cells, and rarely tuberculoid granulomas are present.
The Bazin type is very rare and some investigators question its existence. It, too, presents with painful indurated nodules on the lower legs of middle aged women. Ulceration may also occur. This disease is a hypersensitivity reaction to a tuberculosis infection, a tuberculid. The Mantoux skin test is usually positive and active tuberculosis can usually be demonstrated. Polymerase chain reaction (PCR) analysis of the skin lesions has revealed Mycobacterium tuberculosis DNA in 25% of cases.
Histopathologically, the findings are less specific than the Whitfield type. There is a lobular panniculitis usually associated with a vasculitis. Fat necrosis may be prominent and small tuberculoid type granulomas may be present in the septa and lower dermis around eccrine glands.
Weedon D. Weedon's Skin Pathology. Churchill Livingstone. 1997.
Pannicultis-See term.
Last Updated 4/1/2001
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