Pathology Light microscopy Hematoxylin and eosin-stained section of the skin biopsy involved with a bullous lesion. Junctional bulla formed through the lamina lucida with the lamina densa present at the floor of the bulla and keratinocytes at the roof of the bulla. There are some areas of disruption of the lamina densa by neutrophilic infiltrate and fibrin deposits related to secondary infection and inflammation. There is total absence of the sub-basal dense plaques of the hemidesmosomes of the basal keratinocytes. The rest of the epidermis appears to be within normal limits, with no aggregation of collagen products in the Rough Endoplasmic Reticulum of the basal keratinocytes as one would see in transient bullous dermatosis.
Keratinization appears to be normal.
To access electron micrographs, use Figure 2. This rare type of junctional EB is associated with scarring and atrophy. For a more detailed description and classification of the 26 overlapping phenotypes of Epidermolysis Bullosa, we refer you to recent literature. Transmission electron microscopy has been important for more than 30 years, in identifying the subtypes of Epidermolysis Bullosa, through the ultrastructural examination of the appearances of hemidesmosomes, anchoring fibrils, basal dense placques and the exact location of the split through the basal lamina. Immunofluorescent testing of the basement membrane antigens, such as laminin and type IV collagen often backs up the accuracy of the final diagnosis.