Idiopathic granulomatous mastitis lesion mimicking inflammatory breast cancer.

miparous, came to our clinic at 4 months postpartum with a 3-month history of a painful swelling in her left breast. It had already been drained on several occasions. She had no history of fever, trauma or use of oral contraceptives; her family history was positive for breast cancer. A physical examination revealed ulcerated peau d’orange skin (Fig. 1) above a firm, tender, 8–10 cm mass with an ill-defined border and multiple sinuses, in her left breast. Ipsilateral axillary nodes were palpable. Her hemoglobin level was 110 g/L; leukocytes, 5400/mL. Her erythrocyte sedimentation rate was in the normal range, and a radiograph of her chest appeared normal. Results of a Mantoux test were negative. Ultrasound showed a lobulated, homogeneously hypoechoic 4-cm mass in her left breast. Results of an incisional biopsy reported numerous confluent nonnecrotizing granulomas composed predominantly of Langhans-type giant cells with some lymphocytes (Fig. 2). In our differential diagnosis, we considered tuberculosis, sarcoidosis and fungal granuloma in addition to granulomatous mastitis. In light of the normal Mantoux results, chest radiograph and erythrocyte sedimentation rate, we proceeded with a working diagnosis of idiopathic granulomatous mastitis. We prescribed prednisolone, 20 mg/d; the sinuses and ulcers resolved within 3 weeks (Fig. 3).