<p>70-year-old man with chronic lymphocytic leukaemia suffered from widespread, histologically proven cutaneous lichen planus responding to topical corticosteroids. 2 years later; he presented with painful erosive stomatitis and increasing dyspnoea. Histology, direct and indirect immunofluorescence were done. Initial examination exhibited multiple fibrin-covered erosions of the vestibular mucosa as well as a small painful ulcer on the left side of the lower lip. Besides some actinic keratosis on the face, no other skin lesions were noted.</p>