Diffuse fasciitis with eosinophilia developing after local irradiation for breast cancer

This case describes a patient who developed diffuse fasciitis with eosinophilia (DFE) after an exaggerated local response to radiation following excision of a lymph node-negative breast cancer. Our patient’s fasciitis was diffuse, involving both upper and lower extremities and the trunk at sites distant from the irradiation and tumor site. The fasciitis progressed after curative excision of the breast cancer rather than concurrently with active breast cancer and persisted despite therapy; there was no tumor reoccurrence. With three published cases linking localized eosinophilic fasciitis with breast cancer, and with the literature suggesting that DFE commonly presents after a traumatic trigger, the possibility that radiation therapy for breast cancer could be one such trigger is an important insight for clinicians treating the many patients who undergo breast cancer treatment each year.