What happened, in summary

A 59-year-old woman presented in October 2023 after noticing a right breast lump for about a year. Imaging showed a large breast mass and enlarged axillary lymph nodes, but no distant spread. Biopsy confirmed invasive ductal carcinoma with associated ductal carcinoma in situ. The cancer was classified as Stage III and described as luminal B, HER2-positive.

She received 6 cycles of neoadjuvant docetaxel, carboplatin, trastuzumab, and pertuzumab. During treatment she developed progressive itching, skin hardening, swelling, and pigmentation that spread from the breast to her face, trunk, and limbs. Further testing led to a diagnosis of systemic sclerosis.

After medical treatment improved some of the skin tightness, she underwent modified radical mastectomy. Trastuzumab and pertuzumab were restarted a month later, but after 2 cycles the systemic sclerosis became much worse, with severe skin fibrosis, painful swollen joints, ulcers, and reduced mobility. Targeted therapy was stopped. Radiation was also deferred because of the risk of worsening the fibrosis. Three months later, her systemic-sclerosis symptoms had improved and no breast-cancer recurrence or metastasis was detected.