Preoperative Fibrinogen and Hematological Indexes in the Differential Diagnosis of Idiopathic Granulomatous Mastitis and Breast Cancer.

: Studies on hematological parameters in the differential diagnosis of idiopathic granulomatous mastitis (IGM) and breast cancer (BC) are limited. This study investigated whether preoperative fibrinogen and hematological indexes can be used in the differential diagnosis of patients with IGM and early-onset BC. : Fifty patients with BC, 55 patients with IGM, and 50 healthy volunteer women were included in the study. : There was a statistically significant difference between the IGM and the BC with respect to fibrinogen, fibrinogen/albumin (Fib/Alb) ratio, C-reactive protein (CRP), white blood cells (WBC), neutrophils, neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and monocyte values. When fibrinogen ( < 0.001), the Fib/Alb ratio ( < 0.001), CRP ( < 0.001), WBC ( < 0.001), neutrophil ( < 0.001), NLR ( < 0.001), monocyte ( = 0.008), and 2-hour sedimentation rate ( < 0.001) were compared between the groups, the highest levels were found in the IGM group. There was a negative relationship between CRP and albumin, and a positive relationship was observed between CRP and WBC, NLR, PLR, and 2-h sedimentation rate. CRP had the highest sensitivity (95%), whereas the Fib/Alb ratio (86%) had the highest specificity. Patients with recurrent IGM had increased fibrinogen, Fib/Alb, CRP, neutrophils, NLR, and 2-h erythrocyte sedimentation rate (ESR) and decreased lymphocyte levels compared to non-recurrent patients. : Preoperative CRP, albumin, fibrinogen, Fib/Alb, WBC, neutrophil, NLR, monocyte, and 2-h ESR have considerable potential to be early and sensitive biomarkers of IGM caused by inflammation compared to BC. These parameters also have a significant effect on the recurrence of the disease, suggesting their potential as a practical guide for the differential diagnosis of BC from IGM.