Primary cutaneous marginal zone lymphoma as a complication of radiation therapy: Case report and review.

Background: The occurrence of primary cutaneous B-cell lymphoma at the site of radiation therapy is exceptional. We report herein the case of a primary cutaneous marginal zone lymphoma arising at the site of radiotherapy for breast cancer.

Methods/results: A seventy-year-old woman was diagnosed in 2005 with an invasive ductal carcinoma of the left breast, which was treated with surgery, adjuvant chemotherapy, and radiation therapy. Three years later she developed several cutaneous nodules on her left breast, followed by similar lesions on her back. Histologic, immunohistochemistry, and molecular findings were consistent with the diagnosis of cutaneous marginal zone lymphoma. Physical examination was otherwise negative, as well as mammography, total body CT, bone marrow biopsy, and Borrelia serology.

Conclusions: To our knowledge, this is the first published case of primary cutaneous marginal zone lymphoma occurring at the site of radiotherapy. Cutaneous surveillance is proposed from the first year after irradiation in order to detect new primary malignancies, including this rare cutaneous neoplasm.