Clinicopathological Evaluation of Idiopathic Granulomatous Mastitis: A Retrospective Analysis of Sixty Women at Shohada-e-Tajrish Hospital from 2010 to 2019

Background: Idiopathic granulomatous mastitis (IGM) is an uncommon inflammatory disorder, which tends to occur in childbearing women. Although IGM has a benign nature, it can mimic a vast spectrum of diseases and may lead to an erroneous diagnosis of carcinoma. Also, the patients usually experience a prolonged course of the disease, which is distressing. But, the clinicopathological of IGM is nonspecific and not clear enough. Objectives: This study aims at evaluating the clinicopathological aspects of IGM. Methods: This cross-sectional retrospective study was performed in Shohada-e-Tajrish Hospital, Tehran, Iran on patients between 20 to 50 years old, preliminary diagnosed with IGM from 2010 to 2019. Then, the demographic, clinical, ultrasound, and histopathologic features of patients enrolled were evaluated. Results: A total number of 60 women aged 20 to 50 years old and initially diagnosed with IGM were enrolled in this study. Their mean age was 34.5 ± 6.73. Among all participants, 38.3% of patients had a family history of breast cancer. The most common location of the lesion was the upper outer quadrant (UOQ) with the predominance of the left side (36.6%). They were more likely to present with pain, erythema, swelling, and warmth (51.6%) of the breast followed by palpable mass (38.3%). With ultrasound assessment, the results were matched with a tubular hypoechoic mass in 43.3% of the patients, while the remainder showed a tumor-like lesion (21.6%) and abscess formation (15%). Histologically, non-caseating granulomas associated with mixed inflammatory cells (70%) and cystic space formations surrounded by neutrophil aggregations (15%) composed the dominant features. Conclusions: Despite the rarity of the disease, IGM is a diagnostic challenge as it can masquerade various breast conditions. A definite diagnosis needs collaboration of clinical, radiological, and histopathological findings.