Idiopathic granulomatous mastitis mimicking breast cancer: report of two cases.

Idiopathic granulomatous mastitis is a rare inflammatory breast disease of unknown aetiology that is frequently mistaken for breast carcinoma both clinically and mammographically. In this paper, the authors report two cases of idiopathic granulomatous mastitis that occurred in two parous women aged 38 and 45 years. Clinically, both patients presented with a tender palpable lump in the left breast. Mammography showed an poorly-defined mass in both patients with microcalcification in the first case and skin retraction in the second case. Breast lumpectomy was performed in both patients. Histological examination of the surgical specimen revealed non-caseating granulomas confined to breast lobules. Special staining for fungi and tuberculosis were all negative. Correct diagnosis ofidiopathic granulomatous mastitis requires the exclusion of malignancy, other granulomatous disease and infectious aetiologies. Histopathologic examination remains the gold standard for diagnosis. This disease is rare, and therefore the optimum treatment protocol is still being established.