[Bullous lichen sclerosus after radiotherapy].

BACKGROUND: Bullous lichen sclerosus is an uncommon observation after radiotherapy and can be misdiagnosed as a radiodermitis or recurrence of the neoplasia. CASE REPORT: Two women developed bullous lichen sclerosus after radiotherapy. The delay after radiotherapy was 4 months and 10 years respectively. Irradiation dose was 60 and 64 grays. The lesions covered more than the irradiated zone in one case. Stabilization or regression of the lesions was obtained with cases I topical corticosteroids, with acitretine in one case. DISCUSSION: These cases, and similar cases reported in the literature, underline the fact that the condition has only been reported in women. This is probably because of the nature of the neoplasias treated (breast cancer in 20 cases and cervical cancer in 1). The delay to onset of the skin lesions are quite variable. Lichen sclerosus or morphea may be observed in the irradiated zone but may also appear at a distance. These lesions are not associated with recurrence of the initial cancer. As no association between breast cancer and localized sclerodermia has been found, the causal role is probably played by radiotherapy, producing a Koebner phenomena in predisposed tissue.