RIM of the breast is rare, with an estimated incidence of 0.20% [4
]. Its onset ranges from 1 to 12 months [4
], but could be as late as 32 years post-radiotherapy [6
]. Synonyms include radiation port morphea, radiation-induced scleroderma, radiation port scleroderma, post-irradiation morphea, localised scleroderma and circumscribed scleroderma.
RIM can extend beyond the irradiated area. A patient with breast cancer, with the confounding factors of endometrial cancer and pelvic radiotherapy 3 years prior, developed RIM in the breast, abdominal wall and leg at 2, 12 and 54 months respectively, following breast radiotherapy [7
RIM is not an exaggerated post-irradiation fibrosis of the breast. Post-irradiation fibrosis is more common and is primarily a deep subcutaneous and fascial fibrosis with little or no inflammatory infiltrate [6
]. In contrast, RIM is a localised scleroderma of primarily dermal fibrosis (Figure ) due to radiation-induced disturbance in the immune system, vasculature and collagen metabolism. RIM has an initial inflammatory phase and a subsequent 'burnt-out' phase, where the latter displays induration, fibrotic retraction and pigmentation of the breast. The pathophysiology of RIM is thought to be radiation-induced neoantigen formation that subsequently stimulates secretion of transforming growth factor beta (TGF-β). TGF-β strongly induces fibroblast activation, collagen synthesis and, hence, excessive fibrosis [4
There is no definite correlation between tamoxifen use and the development of RIM. However, tamoxifen can induce TGF-β secretion and increase lung fibrosis in breast cancer patients receiving both tamoxifen and radiotherapy [8
Systemic sclerosis is a relative risk factor for developing an exaggerated post-irradiation fibrosis, although this patient had no previous history of systemic sclerosis. Age and radiotherapy parameters such as total radiation dose, dose per fraction and severity of acute reaction do not seem to be significant risk factors for developing RIM [5
Various treatments including oral antibiotics and topical, intralesional or systemic steroids have been used in treating RIM of the breast with varying results [5
]. One patient had improvement without any treatment [6
Morphea has been treated with topical and systemic steroids, colchicine, D-penicillamine, immunosuppressants and cytotoxics such as azathioprine, methotrexate, cyclophosphamide and cyclosporin, plasmapheresis and extracorporeal photopheresis, with variable benefit [9
PUVA therapy in 10 to 20 sessions for morphea has been reported to cause remarkable skin softening associated with a reduction in skin cytokines including TGF-β [9
]. The mechanism of action of PUVA is attributed to the suppression of inflammation and collagen mediators causing a reduction in pruritus, pigmentation and skin tightness.
Any treatment modality should be started promptly to give the best outcome, as fibrosis and atrophy are not reversed by PUVA therapy. Early referral to a dermatologist is therefore recommended.
Reconstructive surgery for morphea of the breast has been reported to give a good cosmetic result [10
]. To the best of the authors' knowledge, no surgery has yet been performed for RIM of the breast.