Is Fibromyalgia Overlooked in Cases of Idiopathic Granulomatous Mastitis? A Cross-Sectional Controlled Study

Introduction: The purpose of this study was to determine the prevalence of fibromyalgia (FM) syndrome in those with idiopathic granulomatous mastitis (IGM) and to assess the correlations between anxiety, depression, fatigue, sleep quality, and overall quality of life (QOL). Methods: Seventy-six patients with idiopathic granulomatous mastitis (IGM) confirmed by tru-cut biopsy and 62 age- and sex-matched non-IGM group were enrolled. Fibromyalgia (FM) was diagnosed according to the American College of Rheumatology criteria. Participants completed the Fibromyalgia Impact Questionnaire-Revised (FIQR), Visual Analog Scale (VAS), Beck Anxiety Inventory (BAI), Beck Depression Inventory (BDI), Functional Assessment of Chronic Illness Therapy–Fatigue (FACIT-Fatigue), Pittsburgh Sleep Quality Index (PSQI), and Short Form-36 Health Survey (SF-36). Results: The mean age was similar between the IGM and non-IGM groups (34.25 ± 8.09 vs. 32.54 ± 8.67 years). FM prevalence was significantly higher in patients with IGM than in controls (36.8% vs. 6.5%). Patients with IGM had significantly worse VAS, BAI, BDI, FACIT-Fatigue, PSQI, and FIQR scores (all p < 0.001). Within the IGM group, patients with FM had significantly poorer quality of life and worse clinical outcomes than those without FM (all p < 0.001). FIQR scores were significantly correlated with quality of life measures. In multivariable analysis, older age and higher BMI were independently associated with lower odds of fibromyalgia, whereas breastfeeding was an independent predictor of fibromyalgia. Conclusions: Fibromyalgia is significantly more common in patients with idiopathic granulomatous mastitis than in the non-IGM group and is associated with greater symptom burden and poorer quality of life. Screening for fibromyalgia may improve the comprehensive management of patients with IGM.