[Generalized bullous pemphigoid induced by radiotherapy]. / Pemphigoïde bulleuse généralisée induite par une radiothérapie.

ABSTRACT

BACKGROUND: There have been a very small number of reported cases of radiotherapy-induced autoimmune bullous disease. We describe a case of generalised autoimmune sub-epidermal bullous pemphigoid (BP) induced by radiotherapy in a female patient presenting squamous cell carcinoma of the vulva. CASE REPORT In June 2008, a 48-year-old woman underwent vulvectomy with lymph node curettage for squamous cell carcinoma of the vulva. Following surgery, adjuvant radiotherapy was indicated. At the 16th session (dose of 32 Gy), erythema occurred on the irradiation field. At the 23rd session (46 Gy), the patient presented bullous lesions that became generalised after four days with involvement of the oral mucosa. Skin biopsy revealed sub-epidermal bullae and direct immunofluorescence showed continuous linear deposits of IgG and of C3 along the dermal-epidermal junction. Indirect immunofluorescence revealed the presence of antibodies directed against the basement membrane. A favourable outcome was achieved under systemic corticosteroids. No immunotransfer analysis of serum or any other immunological investigations were performed. DISCUSSION: The clinical and histological features of this autoimmune bullous disease were evocative of BP, despite the absence of any formal proof. Radio-induced BP is extremely rare, with only 28 cases being described to date in the literature. The trigger mechanism is poorly understood; radiotherapy appears to cause changes in the antigenic properties of proteins in the dermal-epidermal junction resulting in production of autoantibodies. The radio-induced nature of BP does not affect therapeutic response. The case we report is novel in terms of both generalisation of the eruption and mucosal involvement.