Idiopathic Granulomatous Mastitis (IGM) is an uncommon benign chronic inflammatory condition of the breast, occurring most commonly in women of childbearing age with a higher incidence in certain geographical areas. The aetiology is uncertain and diagnosis is difficult; it is usually made by exclusion. The clinical and radiological features often overlap with those of other benign diseases of the breast in women, but also with those of breast cancer, which is why early diagnosis is necessary to allow timely intervention when required. Its evolution is unpredictable and there is currently no consensus on the optimal treatment for these patients. The aim of this book is to provide readers with an overview of the data available to date on this unknown and controversial disease. General surgeons, breast surgeons, general practitioners, internal medicine specialists, pathologists, radiologists, rheumatologists, immunologists and dermatologists will certainly benefit from this practical guide.