The granulomatous mastitis is uncommon inflammatory disease of the breast of unknown etiology. The diagnosis is obtained only through hystopathology. We report a case of woman, 41 years old, showing lesions of the breast, that caused strong pain with ulcerations sero-haematic secretion and axillary omolateral lymphadenopathy. The diagnostic workup (sonography, mammography, multiples FNAB of single lesions, the culture of cells and hormonal profile) showed an inflammatory aspecific lesions with presence of atipic cells in nipple's secretion and in FNAB of periareola lesion. We performed an excisional biopsy. The hystopathologic diagnosis showed a granulomatous mastitis, confirming the validity of our diagnostic and therapeutic choices. The excisional biopsy has allowed to avoid an overtreatment and obtain a good aesthetic result.