Granulomatous mastitis

Granulomatous mastitis can be divided into idiopathic granulomatous mastitis (also known as granular lobular mastitis^[1]) and granulomatous mastitis occurring as a rare secondary complication of a great variety of other conditions such as tuberculosis and other infections, sarcoidosis and granulomatosis with polyangiitis. Special forms of granulomatous mastitis occur as complication of diabetes. Some cases are due to silicone injection (Silicone-induced granulomatous inflammation) or other foreign body reactions.^[2][3]

Idiopathic granulomatous mastitis (IGM) is defined as granulomatous mastitis without any other attributable cause such as those above mentioned. It occurs on average two years and, almost exclusively, up to six years after pregnancy, usual age range is 17 to 42 years. Some cases have been reported that were related to drug induced hyperprolactinemia.^[4][5] It has been exceptionally rarely diagnosed during pregnancy and in men.^[6][7]

Primary presentation of any of these conditions as mastitis is very rare and in many cases probably predisposed by other breast or systemic conditions. Although granulomatous mastitis is easily confused with cancer it is a completely benign (non-cancerous) condition. Treatment is radically different for idiopathic granulomatous mastitis and other granulomatous lesions of the breast. The precise diagnosis is therefore very important.