ATLANTA – Methotrexate, in combination with prednisone, might be emerging as the go-to option for idiopathic granulomatous mastitis, according to investigators from Oregon Health & Science University, Portland.
Idiopathic granulomatous mastitis (IGM) is an inflammatory disease in which granulomas form in breast tissue. It strikes mostly young to middle-aged women with painful, firm breast masses, sometimes with redness and drainage. Diagnosis is by biopsy with rule-out of known causes.
IGM does not respond to antibiotics. Prednisone and surgery have been the traditional approaches, but masses can recur after surgery, and a year or more of prednisone, with the weight gain and side effects, is problematic. As a result, cases are increasingly being referred to rheumatologists for other options, said lead investigator, MD, a rheumatology fellow at the university.
A study she presented at the annual meeting of the American College of Rheumatology and previous work from others builds a case for methotrexate, which often seems to put the disease in remission and allows for shorter glucocorticoid courses. These days, “I offer this to patients as a great option. It’s really nice to have, instead of having women go on months and months of high-dose steroids, and I think we can save patients from unnecessary” surgery, Dr. Ringsted said.
Her usual regimen these days is methotrexate 15-20 mg/week for 12-18 months, with high-dose prednisone (greater than 20 mg/day) for the first 3 months, followed by a taper.
Dr. Ringsted and associatestreated at the university during 2007-2018. Just 5 of the 12 women (42%) treated with high-dose prednisone alone went into remission and did not relapse over a mean follow-up of 27 months. Two out of three women who had both high-dose glucocorticoids and surgery achieved remission without relapse, as did all three women who received methotrexate and high-dose glucocorticoids (one also had surgery). Five other patients were treated with other options; just two had a durable remission.
The numbers are small, but they add to two previous reports. Among 19 women who had failed other treatments, 94% improved and 75% went into remission with 15 months of methotrexate in afrom Stanford (Calif.) University. An Iranian of 17 patients treated with methotrexate, and also glucocorticoids in some, had a relapse rate of only 17.8%.
There were several cases of both inflammatory arthritis and erythema nodosum in the Oregon series, a higher incidence than what has been reported before for IGM. “It’s interesting because it makes me think of sarcoidosis. There have been cases of sarcoidosis causing mastitis, but mostly in patients with other features” of the disease. “It makes me wonder if any of these women will develop sarcoidosis later on; I think that’s an interesting question,” Dr. Ringsted said.
Women in the study were an average age of 32 years, and over half were Hispanic, which is associated with a higher risk for IGM. Almost all the women had been pregnant before and had breast fed in the previous 5 years. Cancer, tuberculosis, and fungal infections were among the things ruled out before mastitis was deemed idiopathic.
Women with IGM tend to be of childbearing age, and must be cautioned against the teratogenic effects of methotrexate, Dr. Ringsted noted.
There was no external funding, and the investigators didn’t report any disclosures.
SOURCE: Ringsted S et al. Arthritis Rheumatol. 2019;71(suppl 10), Abstract