Erythema nodosum associated with idiopathic granulomatous mastitis in young pregnant woman

Idiopadiic granulomatous mastitis (IGM) is a rare chronic inflammatory condition of unknown etiology. It occurs in young, parous women who had experienced breast feeding, and is manifested as a tender breast mass. Histologically, a discrete granulomatous lobulitis consisting of giant cells, neutrophils, epitheloid cells, and foamy macrophges is shown. Extramammary manifestations of IGM are rare. Erythema nodosum (EN), arthralgia, and episcleritis have been reported, supporting the theory that there is an autoimmune component in the etiology of IGM. Coincidence of IGM and EN is rare. Herein, we report a 28-year-old pregnant woman in whom granulomatous mastitis presented with arthralgia and EN.