Clin Oncol (R Coll Radiol)
Vitiligo and radiotherapy: the Koebner phenomenon demonstrated in patients with vitiligo undergoing radiotherapy for carcinoma of the breast.   
ABSTRACT
We report the case histories of two patients with vitiligo who developed depigmentation of the treated skin area following radiotherapy for carcinoma of the breast. They illustrate the Koebner phenomenon, whereby depigmentation occurs as a trauma response in patients with vitiligo.

Related Questions

There have been case series published on this topic (most recently, PMID:26853347) with reported depigmentation within the RT treatment field.