[Idiopathic granulomatous mastitis: a condition with no definitive treatment].

Idiopathic granulomatous mastitis (IGM) is a rare chronic inflammatory disease of the breast that simulates other diseases, such as cancer, abscess and periductal mastitis. It does not present defining characteristics on imaging diagnostic tests and treatment continues to be controversial. We present 3 cases of IGM that were diagnosed in our hospital over the course of a year. The patients were 41, 34 and 36 years old. They all presented with painful breast lumps: the first 2 patients had solitary lumps and the third had bilateral lumps (2–5 cm in size). They reported no history of trauma or contraceptive use. In the first patient, the lesion had inverted the nipple, although no inflammatory signs were observed in any of the patients. All patients had been pregnant followed by prolonged breastfeeding in the last 4 years. In all 3 patients, ultrasound studies revealed poorly defined hypoechoic lesions (Fig. 1) with no axillary involvement. Mammography demonstrated a nodule in the left lower quadrant of the right breast in only one patient, while in the other 2 the test was negative. Magnetic resonance imaging (MRI) showed alterations consistent with malignancy and breast abscesses in the second and third patients, while in the first patient the test was negative. In one patient, fine needle aspiration (FNA) was performed, which provided no diagnostic data. Meanwhile, in all three cases core needle biopsy (CNB) established the diagnosis of necrotizing granulomatous mastitis (Fig. 2). Ziehl, PAS and Giemsa stains as well as bacteriological cultures for tuberculosis and fungi were negative. The lesion was excised in one patient and, after 18 months, no relapse has been detected. The other 2 patients developed fistulas (in one at the site of the puncture and in the other the fistulas were bilateral and periareolar); cultures were negative in both cases. The fistulas received no treatment other than local therapies. Two patients, one 5 months and the other 3 months after diagnosis, are asymptomatic and have had no lesions either on examination or on ultrasound. IGM was first described in 1972 by Kessler and Wolloch. Average age at diagnosis is 36 (18–67 years) years. Most women have a history of pregnancy or breastfeeding in the previous 5 years. The prevalence of this disease is unknown, although one study reported IGM in 1.8% of 1106 women with benign breast disease. This condition has been detected more frequently among Asian or Hispanic women. In our series, 2 patients