Epidermolysis bullosa complicated by squamous cell carcinoma: report of 10 cases.

Epidermolysis bullosa (EB) refers to a group of hereditary mechano-bullous conditions, many of which are associated with chronic scarring. Several forms of the disease have been reported in association with cutaneous malignancy. We present a series of 10 EB patients (eight generalised recessive dystrophic EB, one dominant dystrophic EB, one non-lethal junctional EB) aged 24-55 years with a total of 29 squamous cell carcinomas (SCC). Three patients died from metastatic disease associated with invasive, poorly differentiated SCC. Six cases had multiple primary SCC, including three patients with simultaneous multifocal disease. Twenty-eight of the 29 SCC arose on the limbs. Histology revealed that most of the SCC were well or moderately differentiated (22/29). Unusual histological findings included two verrucous SCC, as well as a spindle cell (angiosarcoma-like) SCC. Most of the SCC developed in areas of chronic non-healing ulceration (10/29) or longstanding hyperkeratotic crusting (14/29). The dermis around or beneath the carcinomas was densely scarred, more so than in non-malignant areas. In some cases it was difficult to distinguish the clinical appearances of certain areas of chronic ulceration, scarring, and crusting typical of dystrophic EB from many of the SCC. This study underlines the need for constant vigilance for the development of carcinomas in this group of patients, the occasional diagnostic difficulty, and the potential for metastasis.