Histopathological IGG4 Dye and Its Relation with Serum Inflammatory Markers in Idiopathic Granulomatous Mastitis

Idiopathic granulomatous mastitis (IGM) is a rare inflammatory disease of the mammary gland with an unknown etiology. The disease starts as an inflammatory mass in the mammary gland and the differential diagnosis from malignant diseases is important. There is no consensus about treatment; however, immunsuppressive drugs and surgery are recommended. IgG4-associated granulomatous mastitis is a subgroup of IGM and manifests itself as tumor like growth in more than one exocrine gland, extranodal regions and mammarian gland. Histopathologically, there is an increase in lymphoplasmacytic infiltration, stromal sclerosis and IgG4 + plasma cell count. Even though IgG4 related granulomatous mastitis is well defined disease in the literatüre, there is not enough data abaut the IgG4 positivity in this disease. The aim of our study was to determine the IgG4 positivity rate in patients with IGM and to evaluate the differences in serum inflammation markers, disease presentation and disease course among IgG4 positive and negative patients. For this purpose, 55 patients diagnosed with granulomatous mastitis in our clinic between the years 2003-2017 were included in the study. 14.5% of these patients were found to be compatible with IgG4associated mastitis. In IgG4-related and unrelated patients, demographic characteristics, serum erythrocyte sedimentation rate, C-reactive protein, procalcitonin, complement 3 and 4 levels, histopathologic evaluation, baseline lesion size, response to treatment 6 months and it's relationship with abscess-fistula status were evaluated. There was a statistically significant difference between the two groups in terms of age of diagnosis but no difference was found in other parameters. The general impression concluded in this study is that although idiopathic granulomatous mastitis is a disease that can ocur because of multiple etiological factors, IgG4 negativity or positivity does not make a difference in terms of it's presentation and response to treatment. Diagnosis of idiopathic granulomatous mastitis should be supported by histopathology but IgG4 studies are not routinely required in the pathologic specimens because IgG4 positivity has no clinical and therapeutic effect. Keywords: Idiopathic granulomatous mastitis, IgG4, Corticosteroid