Epidermolysis bullosa simplex with mottled pigmentation. Case report and review of the literature.

Epidermolysis bullosa simplex with mottled pigmentation (EBS-MP) is a rare genodermatosis of which only 4 pedigrees have so far been reported. We present herein a new family with EBS-MP comprising a peculiar punctate digital keratoderma. The propositus was an 18-year-old patient who had suffered since birth from posttraumatic bullae, followed by mottled pigmentation, plantar keratosis, nail dystrophy and peculiar punctate keratoses of the fingers. Histology, immunofluorescence and electron microscopy of a bullous lesion showed an intraepidermal cleavage and an increased number of melanosomes within basal keratinocytes, dermal macrophages and Schwann cells. The precise genetic defect responsible for EBS-MP is not known but could be due to two distinct, closely linked mutations. The nosologic relationship between EBS-MP and other forms of EBS as well as cases of hereditary bullous poikilodermic acrokeratosis is discussed.