Several cases occurring together with fever, polyarthralgia and erythema nodosum were documented. Diagnosis
Characteristic for idiopathic granulomatous mastitis are multinucleated giant cells and epithelioid histiocytes forming non-caseating granulomas around lobules. Often minor ductal and periductal inflammation is present. The lesion is in some cases very difficult to distinguish from breast cancer and other causes such as infections (tuberculosis, syphilis, corynebacterial infection, mycotic infection), autoimmune diseases (sarcoidosis, granulomatosis with polyangiitis), foreign body reaction and granulomatous reaction in a carcinoma must be excluded.The condition is diagnosed very rarely. As the diagnosis is a lengthy differential diagnosis of exclusion there is considerable uncertainty about incidence. It has been suspected that some cases diagnosed as IGM in developing countries may have other explanations. On the other hand, IGM is usually diagnosed only after complications and referral to a secondary breast care center so light cases may resolve spontaneously or after symptomatic treatment and thus never be diagnosed as IGM. As a completely pathogen free breast will be exceedingly rare even in completely healthy population there is also uncertainty when to consider pathogens as causative or as mere coincidental finding. Causes of idiopathic granulomatous mastitis
Causes are not known. The histology is suggestive of an autoimmune reaction. The high rate of relapses as well as relatively high proportion of bilateral cases is highly suggestive of a systemic predisposition. Presently most evidence points towards an important role of elevated prolactin levels or overt hyperprolactinemia with additional triggers such as local trauma or irritation.
This organism, first isolated from human sputum in 1998, requires lipids for its growth which may help to explain its association with this condition. Treatment
Treatment protocols are not well established. Some sources report that approximately half of the patients will fully recover after 2–24 months management.One review recommended complete resection or corticosteroid therapy, stating also that long-term follow-up was indicated due to a high rate of recurrence. Treatment with steroids usually requires about 6 months. While some source report very good success with steroids, most report a considerable risk of recurrence after a treatment with steroids alone. Steroids are known to cause elevation of prolactin levels and increase risk of several conditions such as diabetes, and other endocrinopathies which in turn increase the risk of IGM. For surgical treatment, recurrence rates of 5-50% have been reported.Treatment with a combination of glucocorticoids and prolactin lowering medications such as bromocriptine or cabergoline was used with good success in Germany. Prolactin-lowering medication has also been reported to reduce the risk of recurrence. In cases of drug-induced hyperprolactinemia (such as antipsychotics) prolactin-sparing medication can be tried.Methotrexate alone or in combination with steroids has been used with good success. Its principal mechanism of action is immunomodulating activity, with a side effect profile that is more favorable for treating IGM.Colchicine, azathioprine, and NSAIDs have also been used. References


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