Ultrastructural features of ichthyosis hystrix strongly resembling Lambert type.

Ichthyosis hystrix (IH) is characterized by spiny hyperkeratotic scale, and includes Brocq type, Lambert type, Curth-Macklin type, Rheydt type and Bäfverstedt type. The first documented cases of familial IH were of Lambert type. However, the ultrastructural features of IH Lambert type have not been reported. Three patients in two generations of a family from north China were observed. The patients showed widespread verrucose lesions without blister formation. The face, palms and soles were unaffected. This presentation strongly resembled IH Lambert type. The lesions faded dramatically in summer, without treatment. Light microscopic examinations showed binuclear cells and shell formation in the granular and upper spinous layers in all specimens, with similar findings in winter, when lesions were prominent, and in summer, when lesions had subsided. Electron microscopic examination revealed binuclear keratinocytes and concentric, thin to thick, unbroken shells of tonofilaments surrounding the nuclei, and segregation of cytoplasmic components. This family is the first with familial IH strongly resembling Lambert type to be reported in China. Binuclear cells and tonofilaments shells surrounding the nucleus in upper keratinocytes were characteristic features, which were similar to those reported in IH Curth-Macklin type. The basic histopathological defects were not changed despite significant clinical improvement of the lesion.