Vinita Thakur - Division of Breast and Women's Imaging, Department of Diagnostic and Interventional Radiology, Kovai Medical Center and Hospitals, Coimbatore, Tamil Nadu, India
Rupa Renganathan - Division of Breast and Women's Imaging, Department of Diagnostic and Interventional Radiology, Kovai Medical Center and Hospitals, Coimbatore, Tamil Nadu, India
Prema Subramaniam - Division of Breast and Women's Imaging, Department of Diagnostic and Interventional Radiology, Kovai Medical Center and Hospitals, Coimbatore, Tamil Nadu, India
P Prathiba Rajalakshmi - Division of Breast and Women's Imaging, Department of Diagnostic and Interventional Radiology, Kovai Medical Center and Hospitals, Coimbatore, Tamil Nadu, India

Background: Granulomatous lobular mastitis (GLM) is a rare inflammatory disease of the breast. Its clinical features and imaging findings often mimic malignancy. The aim of this study is to review the mammographic and ultrasound features of granulomatous lobular mastitis to help differentiate it from other diagnoses. Methods: In our study, imaging data of ۵۱ patients were reviewed retrospectively, who were diagnosed with granulomatous lobular mastitis by core needle biopsy and culture analysis. Results: The mammographic findings of granulomatous lobular mastitis observed in our study group were focal or global asymmetry (۵۲.۶%), oval or round lesions with obscured margins (۱۵.۷%), irregular mass with indistinct margins (۱۵.۷%) and associated skin thickening (۲۶.۳%) with no specific pointers to differentiate from malignancy.The most common morphological abnormality on ultrasound was single or multiple collections with or without tracts (۷۲.۵%). Other morphological abnormalities were non-mass areas with tracts (۲۵.۵%), dilated ducts with debris (۱۳.۷%) and mass (۳.۹%). The common associated abnormalities were perilesional increased echogenicity (۸۶.۳%), increased peripheral vascularity (۸۸.۲%), intercommunicating tracts (۷۶.۵%) and axillary adenopathy (۶۸.۶%) and these ultrasound features were pointers to differentiate granulomatous mastitis from malignancy. Conclusion: Granulomatous lobular mastitis has non-specific clinical and imaging features. Imaging, especially ultrasound as in our study, is found to be indispensable in diagnosing GLM and excluding other causes such as infective mastitis and malignancy.