Concomitant Radiation Recall Dermatitis and Organizing Pneumonia following Breast Radiotherapy: A Case Report

Purpose Radiation recall dermatitis (RRD) is a rare complication that occurs after completion of radiation therapy (RT) and initiation of a precipitating agent, most commonly chemotherapeutic medications. Various theories attempt to explain the mechanism, including activation of the body's inflammatory pathways through nonimmune activation. Likewise, radiation-induced organizing pneumonia (RIOP) is an infrequent but potentially life-threatening complication of RT that, while not fully understood, is suspected to be partly an autoimmune reaction. Patient We present the case of a 71-year-old female with a history of type 2 diabetes mellitus, hypothyroidism, interstitial cystitis, and osteoarthritis who presented with clinical stage T1N0M0 ER+/PR-/HER2- invasive ductal carcinoma of the lower outer quadrant of the left breast, for which she underwent left segmental mastectomy and sentinel lymph node biopsy followed by completion axillary lymph node dissection. Her final pathologic stage was T1N1M0. Result The patient developed RRD and later RIOP following receipt of radiation and chemotherapy, which resolved with steroid administration. Conclusions The rarity of both RRD and RIOP occurring in a patient, as in our case, suggests a shared pathophysiology behind these two complications. As both reactions involve some degree of inflammation and respond to corticosteroids, it seems likely that the etiologies of RRD and RIOP lie within the inflammatory pathway. However, further investigation should evaluate the frequency, duration, and triggering of concomitant RRD and RIOP.