Localized polyarteritis nodosa of breast--report of two cases and a review of the literature.

Two patients with localized polyarteritis nodosa involving the breast are reported. They presented with tender breast masses which were excised because of suspicion of carcinoma. The pathological features were similar with vasculitis of medium-sized and small arteries. The medium-sized arteries showed intimal fibroplasia, fragmentation of internal elastic lamina and inflammatory cellular infiltration. Fibrinoid vasculitis involving small arteries indicated a diagnosis of polyarteritis nodosa rather than giant cell arteritis. Both patients remain well. The differential diagnosis of these two arteritides and of Wegener's granulomatosis involving the breast is reviewed.