Radiation-associated lichen planus: a case report and literature review.

Percutaneous radiotherapy (RT) may cause a range of acute and chronic cutaneous side-effects on irradiated areas. Localized or generalized lichen planus (LP) has occasionally been reported after RT. The mechanisms of LP are unclear. A case report and a systematic review of the literature were performed. Including the present case, 12 cases of LP have been reviewed in association with oncologic radiotherapy since 2002. Of these, 83% of patients developed LP after RT. LP occurred with a median delay of 30.7 days after RT completion and a median dose of 50 Gy. LP is a rare complication during RT that mainly occurs at the site of radiation and can sometimes spread and become generalized. Its physiopathogeny remains unclear. In some cases, patients may have preexisting but asymptomatic LP before RT. RT would therefore act as an indicator of the disease. The treatment of RT-associated LP is similar to that for any LP.