An Unusual Case of Bilateral Granulomatous Mastitis

Idiopathic granulomatous mastitis (IGM) is an uncommon benign disorder of the breast. At clinical examination, IGM is characterized by an inflammatory process of the breast, usually unilateral. Possible clinical findings are palpable mass with erythematous skin, pain, sterile abscesses, fistula and nipple retraction. Mammography and ultrasound findings are not specific for IGM. Magnetic resonance imaging (MRI) is a useful tool for the differential diagnosis; it is also necessary to delineate the exact extension of the disease and to plan the correct treatment. Final diagnosis is histological. We described an unusual case of IGM with bilateral involvement in a patient with history of pacemaker implantation and IGM typical clinical symptoms. Mammography, ultrasound, and MRI examinations were performed to identify the inflammatory disorder and to plan the correct therapy. Imaging features were correlated with final histological diagnosis of IGM. 1. Introduction Idiopathic chronic granulomatous mastitis is a rare benign inflammatory breast disease. In a study done by Baslaim et al. histopathology confirmed cases of IGM represented 1.8% of cases out of 1,106 women with benign breast diseases. The true prevalence of IGM is unknown. IGM is an idiopathic condition. Mechanisms that have been proposed as etiologic factors include chemical reaction associated with oral contraceptive pills, pregnancy, breast feeding, autoimmune phenomenon, infection with yet unidentified pathogens, breast trauma, hyperprolactinemia with galactorrhea, and alpha-1-antitrypsin deficiency [1, 2]. IGM remains a diagnosis of exclusion, and the clinical findings are nonspecific [3]. Clinically, IGM presents as an inflammatory process of the breast that can mimic an inflammatory cancer or an abscess [4]. At initial presentation, the most common clinical finding is a palpable mass with erythematous skin changes [5, 6]. Other reported clinical symptoms include pain, sterile abscesses, fistula and nipple retraction. Unilateral involvement is typical; bilateral IGM is uncommon although it has been reported in the literature [7, 8]. Radiological findings are not specific for IGM. Mammographic and ultrasonographic most frequent findings are asymmetric diffuse increased density of fibroglandular tissue and hypoechoic mass lesions or nodular structures, respectively. Breast magnetic resonance imaging (MRI) can be useful to characterize the lesions, but it is not diagnostic. Histopathological evaluation plays a crucial role in the diagnosis of IGM [9]. Treatment includes an initial conservative