Dyskeratosis congenita: a light microscopic and ultrastructural study.

We have examined, histologically and ultrastructurally, a case of dyskerato-sis congenita in a 46-year-old man. Clinically, a net-like pigmentation with partial poikiloderma atrophicans vasculare was observed. Dystrophic changes of the nails and whitish thickening of the oral mucosa were also present. Histological examination showed atrophy of the epidermis, disappearance of the rete ridges and cleft formation of dermo-epidermal junction. Vacuoles could be seen on electron microscopy in the cytoplasm of basal cells and above the basal lamina. Tonofibrils in the cytoplasm of basal cells were decreased in number and size. Duplication or multiplication of basal lamina was also seen. From these results, it appears that the vacuoles observed ultrastructurally correspond to the cleft of the dermo-epidermal junction seen by light microscopy and that atrophy of the epidermis and/or disappearance of rete ridges result from sporadic degeneration of basal cells.