Idiopathic granulomatous mastitis is a rare chronic benign inflammatory mastopathy occurring mainly in young women. With a non-specific imagery, it is considered as a diagnosis by exclusion and has a challenging treatment. Histologically, it is characterized by the predominance of polynuclear neutrophils and the absence of caseous necrosis. The breast carcinoma is the main differential diagnosis at the clinical stage, and imagery plays an essential role in its diagnostic approach. Its treatment combines antibiotics, anti-inflammatories, corticosteroid therapy, and surgery. We report a 42-year-old woman who presented a breast lesion diagnosis as granulomatous mastitis based on magnetic resonance imaging, ultrasound, and histology examinations. She received a treatment with different drugs (antibiotics, anti-inflammatories). The outcome treatment was successful with a good healing of breast lesions.