RESUMEN
Presented here is a case report of a 77-year-old woman affected by rheumatoid arthritis (RA) who underwent breast-conserving surgery followed by radiation therapy (RT) for left-breast cancer and developed bronchiolitis obliterans organizing pneumonia (BOOP) after RT and during COVID-19 vaccination campaign. BOOP incidence is an uncommon morbidity after breast RT (1.2-2.9%), however, specific predisposing factors can play a role. In this patient, both, RA and vaccine may have predisposed her to an increased risk of organizing pneumonia, probably by triggering a pro-inflammatory cascade. Our report highlights the importance of factors that influence the occurrence of uncommon radiation induced morbidities such as BOOP in specific subsets of patients. Further studies are necessary to evaluate factors increasing radiation sensitivity.