Post‐Radiation Granuloma Annulare: A Series of Three Cases

ABSTRACT We report typical cases of biopsy confirmed granuloma annulare occurring on irradiated skin in the context of breast cancer in three women in their seventies. The lesions appeared immediately after start of irradiation in one patient, 4 and 15 months after the end of radiation treatment in the other two. The lesions eventually spread elsewhere on the body in two patients. Similar to morphea, which is a well‐known side effect of irradiation, we believe that radiotherapy can induce tissue damage, leading to dermal inflammation ultimately responsible for the emergence of granuloma annulare.