MAUI, HAWAII – Methotrexate is the most effective therapy for granulomatous mastitis, according to Anna Postolova, MD, a rheumatology fellow at Stanford (Calif.) University.

Granulomatous mastitis is a rare inflammatory disease of the breast of uncertain but possibly autoimmune etiology. The most common treatments – antibiotics, prednisone, and incision and drainage – are often ineffective and have a roughly 50% recurrence rate. That’s why Stanford rheumatologists began using methotrexate more than a decade ago with impressive results, she explained at the 2018 Rheumatology Winter Clinical Symposium.

Bruce Jancin/MDedge News

Presenting symptoms of granulomatous mastitis include unilateral or bilateral pain, palpable mass, redness, swelling, skin induration, erythema, abscess and/or fistula formation, and discharge. The differential diagnosis involves periductal mastitis, breast cancer, infection, sarcoidosis, and granulomatosis with polyangiitis. Diagnosis of granulomatous mastitis requires histologic examination of a biopsy specimen.

Dr. Postolova presented a retrospective series of 19 women referred to Stanford for recurrent or refractory granulomatous mastitis. At diagnosis, they averaged 33.5 years of age with a 6-month history of symptoms prior to diagnosis. Of the 19 women, 11 were Hispanic, and only 2 were Caucasian. A total of 17 women were multiparous, with an average of two children, and 3 women were breastfeeding at symptom onset.

The women were placed on methotrexate at 15 mg/week. At 3 months, 17 of the 19 patients showed improvement, but none had disease resolution. At that point the dose was raised to 20 mg/week. After 3 months at the higher dose, 16 of 18 patients were improved and 4 had experienced resolution of their granulomatous mastitis. After 9 months on methotrexate – 6 at the higher dose – the granulomatous mastitis showed continued improvement in 13 of 15 women and resolution in 8. One woman experienced recurrent disease at 9 months of follow-up after her methotrexate was withheld because of liver test abnormalities and lack of birth control; however, she went into remission upon restarting therapy.

By 12 months, 12 of 15 women, or 80%, had experienced disease resolution. Their methotrexate was then slowly tapered over the course of 18-24 months without disease recurrence.

On the other hand, two women who had previously shown improvement were experiencing mild recurrences at the 12-month mark. They were switched to subcutaneous methotrexate. One responded favorably to the change, and the other had not yet returned for follow-up.

Dr. Postolova reported having no financial conflicts of interest regarding her presentation.

bjancin@mdedge.com

Think methotrexate for granulomatous mastitis