Dyskeratosis as a histologic feature in epidermolysis bullosa simplex-Dowling Meara

Background Intracellular keratin aggregation and clumping is a characteristic ultrastructural feature in epidermolysis bullosa simplex (EBS)-Dowling Meara (DM) yet without histologic correlates in routinely stained specimens. Objective We sought to detect histologic clues to keratin aggregation and clumping in the involved epidermis of EBS-DM. Methods Four cases of EBS-DM caused by dominant keratin (KRT)5 and KRT14 mutations were studied histologically and ultrastructurally. The histologic slides of 11 additional EBS cases (9 Weber-Cockayne subtypes and two Koebner subtypes) were also reviewed histologically. Results Intracytoplasmic aggregation and clumping of tonofilaments were observed ultrastructurally in all 4 EBS-DM cases. Intracytoplasmic eosinophilic homogenizations and inclusions (ie, dyskeratosis) in individual keratinocytes were detected histologically in 3 of the 4 EBS-DM cases, but in none of the 9 EBS-Weber-Cockayne cases or the two EBS-Koebner cases. Limitations This was a relatively small studied group. Conclusion The histopathological detection of dyskeratosis in individual keratinocytes may provide a valuable clue to keratin aggregation and clumping, and to the diagnosis in EBS-DM.