Lichen sclerosus et atrophicus following radiation therapy.

Several years after postmastectomy radiation therapy, lichen sclerosus et atrophicus (LSA) developed in two patients within the radiation fields. This sequence, to our knowledge, has not previously been described. The etiology of LSA is largely unknown, but trauma has been implicated as a provoking factor in some cases, and LSA might be an isomorphic response to the trauma of radiation therapy.