Idiopathic Granulomatous Mastitis-A Prospective Study of 49 Women and Treatment Outcomes with Steroid Therapy

Abstract

Idiopathic granulomatous mastitis (IGM) is an infrequently reported benign breast disease of unknown etiology. Surgical treatment has been widely advocated but can be disfiguring. We describe demographic and clinico-pathologic features of women with IGM in a safety net hospital, and evaluate steroid therapy as a breast-conserving modality of treatment. We also examine a possible ethnic predominance in Hispanic women. We conducted an observational prospective cohort study of all women with biopsy-proven granulomatous mastitis in the breast clinics of an urban safety net public hospital from 2006 to 2010. Demographic, ethnic and clinical data, treatment history, and response to treatment were collected. Patients were followed up prospectively to determine the type of treatment prescribed, complete resolution of disease, and median time to resolution. A nested case-control study was conducted to examine Hispanic prevalence using chi-square statistic. The mean age was 35 years. 80% were Hispanic. 80% presented with a painful breast mass. 59% initially received antibiotics with incomplete resolution. 90% women were prescribed oral steroids, 3% underwent surgical treatment, and 6% remained under observation with spontaneous resolution. Of those who received steroid, 80% had complete resolution of disease with a median time to complete resolution of 159 days (IQR 120-241 days). Ethnicity data in a nested case-control study revealed that women in the IGM group were more likely to be Hispanic than in the control group with an odds ratio of 3 (95% CI 1.42-6.24, p-value 0.0032). IGM is a benign but locally aggressive breast disease. Treatment with steroids is an effective breast-conserving option. Predominance in Hispanic women of childbearing age suggests a common genetic, environmental, immunologic, or infectious etiology and warrants further study with a multi-disciplinary approach.

Clinical Significance of Commensal Gram-Positive Rods Routinely Isolated from Patient Samples

“…However, awareness of this histopathological entity is lacking, and it is imperative that clinical microbiologists work to educate their colleagues and residents about novel disease associations, such as C. kroppenstedtii mastitis, with characteristic histopathological findings (27). Consistent with data from several recent reports, 7 of 9 patients in our study were of Hispanic descent (11,12,(28)(29)(30)(31)(32)(33). This association may be due to multiparity, breastfeeding, low socioeconomic status, or birth outside the United States with geographic variation in skin flora (1).…”

Idiopathic granulomatous mastitis: diagnosis and follow-up with magnetic resonance imaging

“…In some cases, breast abscess, fibroses and fat necrosis can occur. Reactive axillary lymphadenopathy may also be presented, as in our case report 1,5,8,10,11 . Histology is characterized by a non-caseating granulomatous inflammatory response of the breast lobules in the absence of specific underlying causes.…”

“…Our patient did not show side effects of the steroid therapy, such as glucose intolerance and Cushingoid features 1,8 . A prospective case series demonstrated a successful treatment in the majority (90%) of women by using only the prednisone therapy 11 . The prognosis is good; nevertheless, local recurrence is frequent 5 .…”

The role of dapsone in refractory idiopathic granulomatous mastitis

“…Immunomodulators such as Azathiprine and Methotrexate as well as surgery have also been used in patients with more refractory cases. [1,2] Recurrences can happen in all treatment modalities.…”

“…[1] Environmental and genetic factors may also play a role in the pathogenesis of IGM. [2] IGM classically presents as a unilateral painful breast mass in women who are 30-40 years of age. [1] When first encountered, IGM may mimic infectious mastitis or malignancy.…”