A case series of idiopathic granulomatous mastitis patients and their immunosuppressive management

Background/Aims Rheumatologists are experts in managing immunosuppression andare asked to supervise immunosuppression for non-rheumatic condi-tions. Thus, it is important to be aware of these conditions and theregimes required. Idiopathic granulomatosis mastitis (IGM) is a rareinflammatory breast condition which can have systemic manifesta-tions including arthritis. Methods Our index case presented with peripheral ankle synovitis/tenosynovi-tis, struggling to weight bear, whilst being investigated for a breastmass. Breast US, mammogram and biopsy (acute and chronic inflam-matory cells including multi-nucleated giant cells) were completedand there was little response to 3 courses of antibiotics. No myco-bacteria were seen on microscopy, ZN stain negative, CXR normal, Tspot negative and serum ACE normal. There was no rash and no con-ditions associated with a seronegative spondyloarthropathy. RF, anti-CCP and ANA were negative. A moderate course of prednisolone im-mediately resolved the peripheral arthritis, but high-dose steroidswere required to reduce the breast mass. The mass recurred uponweaning prednisolone requiring the addition of azathioprine as a ste-roid-sparing agent. Results Our case series includes the immunosuppressive management of 3other IGM patients: 1) 43-year-old referred after an 8 year history ofalternating breast'abscesses'and sinuses treated with courses ofantibiotics to little avail. High dose prednisolone and methotrexate re-solved the breast mass within a month. 2) 37-year-old referred with a14 year history of breast masses andfistulae previously treated withsurgery and antibiotics. Currently asymptomatic so commenced onmethotrexate. 3) 39-year-old referred with a 3 year history of recurrent sterile breast abscesses previously managed with antibiot-ics, incision and drainage. Recent small masses had settledwith NSAIDs. Conclusion IGM is a rare benign inflammatory breast disease of unknown aetiol-ogy, commonest in Middle Eastern populations, median age 30s.The most common presentation is a unilateral painful mass, whichcan ulcerate,fistulate and form abscesses. Management of IGMvaries from expectant/topical steroids/NSAIDs to high dose steroidsand DMARDs. A literature review shows that the usual starting doseof prednisolone is 40-60mg; the addition of methotrexate and azathi-oprine increases likelihood of successful treatment and allows forfaster steroid tapering. Surgery for specific types of IGM can also beuseful; for example, where there is duct granuloma, surgical excisioncan be curative. IGM can associate with arthritis, erythema nodosum,and episcleritis. One case series found that 14% of patients withIGM had concomitant arthritis. Key points: In our local experience we have had four patients withIGM, all previously treated with antibiotics or surgical methods butsubsequently diagnosed with IGM and referred for immunosuppres-sive therapy. Being a rare condition, we feel it's important for clini-cians to be aware of IGM and its link with inflammatory arthritis.