Stage I ER-positive/HER2-positive breast cancer with radiation-associated morphea

What happened, in summary

A 77-year-old woman with hypothyroidism had been treated for left breast carcinoma in 2018. The cancer was staged as pT1cN0M0 and tested ER-positive, PR-negative, and HER2-positive. She underwent partial mastectomy with sentinel lymph node biopsy, followed by 1 cycle of adjuvant docetaxel, cyclophosphamide, and trastuzumab. Chemotherapy was stopped early because of significant side effects. She then received 3D conformal external beam radiation to the whole left breast, 40 Gy in 15 fractions, followed by a 10 Gy boost in 4 fractions to the tumor bed, completed in April 2018. During radiation, she developed grade 2 dermatitis with moist desquamation in the inframammary fold, which resolved within a few weeks with routine care. She was prescribed adjuvant anastrozole for 5 years and had no evidence of cancer recurrence. In July 2022, about 4 years after the breast cancer diagnosis, she noticed red-purple skin changes on the left breast. Over the next 3 months, the skin became thickened with a cardboard-like texture, itching, and severe bilateral breast deformity. Changes spread beyond the left breast to the right side, abdominal folds, and along the spine. Breast ultrasound, mammography, MRI, physical examination, and skin evaluation showed no relapse. Skin biopsy showed dermal fibrosclerosis and chronic inflammatory remodeling, supporting generalized morphea related to prior radiation. She was treated first with prednisone, high-potency topical corticosteroids, topical vitamin D, and phototherapy. After partial improvement, mycophenolate mofetil 1 g twice daily was added. As of April 2024, this treatment was well tolerated and provided significant skin-disease control and symptom relief.