Cytotoxic-mediated spontaneous regression of inflammatory cutaneous metastases of breast carcinoma.

Spontaneous regression (SR) of cancer is a rare but well-documented biological phenomenon, which is even rarer in the context of metastatic breast carcinoma. Different mechanisms of SR are still under debate, including immune-mediated response. We herein report a case of the SR of intralymphatic cutaneous metastases of a breast carcinoma with spontaneously-induced T-cell-mediated cytotoxic response. An 86-year-old female was diagnosed with locally advanced right breast carcinoma and axillary lymph node metastases, without distant metastases The patient refused any therapy. Six months afterwards, she developed multiple, asymptomatic purpura-like plaques with prominent teleangectasias on her right chest wall, continuous to the previous surgical scar and on her ipsilateral abdomen. Skin biopsy showed aggregates of atypical cells admixed with erythrocyte thrombi within dilated dermal lymphatic vessels. SR of the cutaneous lesions occurred within 6 months and persisted at the 15 months follow-up in the absence of therapy, whilst no signs of internal relapse were observed. Immunohistochemically, the estrogen-negative, CK7-positive, C-erb B2-positive intralymphatic metastases were associated with extensive infiltration of CD8-positive cytototoxic T lymphocytes. Factors that may have precluded the implantation of intralymphatic metastases leading to SR are discussed, with local immune surveillance being one major hypothesis.