Granulomatous Mastitis Masquerading as Breast Neoplasms- An Enigmatic Series of 14 Cases

Granulomatous Mastitis (GM) is a rare entity encountered in day-to-day practice. Aetiologies range from infections like tuberculosis, lactation, certain medications to being idiopathic. Clinical and radiological pictures in these cases often mimic breast carcinoma that poses diagnostic dilemmas to the treating physician. However, sometimes they may be asymptomatic. Definitive diagnosis is made using cytology followed by histomorphology by demonstration of granulomas, which are collections of histiocytes along with giant cells and inflammatory cells. Ancillary studies like Ziehl-neelsen (ZN) stain, Periodic Acid Schiff (PAS) stain, Cartridge Based Nucleic Acid Amplification Test (CBNAAT) are used to detect or rule out certain aetiologies of granulomatous inflammation. Idiopathic Granulomatous Mastitis (IGM) is mainly a diagnosis of exclusion, where all the possible aetiologies have been ruled out by detailed history and investigations. Treatment approaches are mainly conservative, depending on the cause or may be anti-inflammatory and steroids in case of IGM. Appropriate and timed diagnosis of such cases is essential to prevent over diagnosis of carcinoma and unnecessary mastectomies. This is a series of 14 such cases which were diagnosed using cytology or histology and ancillary tools. They belonged to four categories (namely-Tuberculous mastitis, IGM, Post-chemotherapy GM and sarcoid granuloma of breast). Tuberculous cases shared majority of the series, whereas, sarcoid granuloma was a single isolated entity. All these cases presented with lump in breast with other associated presentations. Immediate tissue diagnosis helped in ruling out malignancy and adopting a conservative approach for management.