Sharing my experience in case it’s useful to anyone weighing rapamycin for cystic neutrophilic granulomatous mastitis (CNGM) or similar granulomatous inflammation. As far as I could find at the time, there were no published cases of rapamycin being used for CNGM when I started. The decision was based on three things: the mechanism (mTOR’s role in granuloma formation and T-cell-mediated inflammation), a personal history of unexplained autoimmune-type issues that suggested a baseline of dysregulated inflammation, and a working hypothesis that if I could lower my systemic inflammatory tone enough, my own immune system would be able to clear the mass without surgical or cytotoxic intervention. I sourced the sirolimus online and kept my GP in the loop for lab monitoring throughout. This was off-label and exploratory. The result has been better than I had any right to expect.
Why I went off-protocol
The standard treatment menu for CNGM - high-dose corticosteroids, methotrexate, antibiotics, surgical excision - has a striking pattern in the published literature: it often fails. Recurrence rates after steroids run high, methotrexate has its own toxicity profile and inconsistent response, and surgical excision frequently leads to recurrence at the margin or contralateral disease. Many patients cycle through multiple modalities over years.
The failure risk isn’t just cosmetic or quality-of-life. There are documented cases in which granulomatous mastitis preceded - or masked - a later breast cancer diagnosis at the same site. Whether that’s coincidence, shared underlying biology, or chronic inflammation as a driver isn’t fully resolved in the literature, but the association is real enough that prolonged unresolved disease shouldn’t be treated as a benign waiting game. Getting it actually resolved matters.
That’s the calculus I was running when I made the case for sirolimus.
Background
- March 2024 (age 36): screening ultrasound caught a small left retroareolar nodule, BI-RADS 4
- July 2024: diagnostic MRI showed a multilobulated peripherally enhancing mass, 1.5 x 1.2 x 1.1 cm, inseparable from the base of the nipple. Core biopsy returned “marked mixed inflammation, granulation tissue, and foreign body-type giant cell reaction,” with CNGM in the differential
- August 2024: breast surgeon declined open biopsy/excision given the imaging-pathology concordance and asymptomatic presentation. Plan was watch-and-wait
- November 2024: mass had clinically enlarged and become tender. Repeat ultrasound in NY confirmed it was still there at ~10 mm and noted an interval increase in size
Protocol
- Course 1: November 2024 — 7 mg once every 6 days for 8 weeks
- Course 2: September 2025 — same protocol, 7 mg once every 6 days for 8 weeks
This is a pulsed/intermittent dosing schedule, total exposure per course is modest.
Results
- Pre-treatment baseline (July 2024 MRI): 15 x 12 x 11 mm
- Documented interval increase by November 2024 (clinical exam + ultrasound)
- Post-course 1 (January 2025 MRI): 6 x 5 x 4 mm - significant reduction noted by the radiologist
- Post-course 2 (March 2026 MRI): no enhancing lesion, BI-RADS 1, complete resolution
No steroids, no methotrexate, no surgery. Side effects were minimal - notably, my skin was less oily, my scalp was less oily, and a separate chronic psoriasis didn’t flare during either course and has stayed quiet since.
Why I’m posting this
I spent a lot of time looking for someone who had tried this and finding nothing. If you’re in the same position - diagnosed with CNGM or IGM, not wanting to go down the steroid/methotrexate/surgery path, weighing the very real risk that conventional treatment won’t actually resolve the disease, and curious whether mTOR inhibition is even on the table - this is one data point in favor. It’s not proof of anything. But the documented progression before starting (interval growth, tender, palpable) and the dose-response pattern across two courses make spontaneous regression a hard explanation.