Ichthyosis hystrix Curth-Macklin type (CM) is a rare autosomal dominant disorder of keratinization, with wide variability of onset and clinical presentation.1,2 Only two families and three solitary cases have been reported so far. This disease is characterized by a pathognomonic ultrastructural pattern consisting of perinuclear shells of unbroken tonofilaments in suprabasal keratinocytes. Electron microscopy is necessary to differentiate this disorder from epidermolytic hyperkeratosis (EH), which shows some clinical and histopathologic similarities. The problem of whether CM belongs to the EH group or is a distinct entity is still unsolved.
Report of a Case.
The patient, a 2-year-old boy, presented with wide areas of nigricans hyperkeratotic skin on the trunk and limbs without any evident desquamation. At the big folds and on the extensor surfaces of the wrists, elbows, and ankles, the hyperkeratosis was prominent and assumed a linear arrangement (Figure 1 ). The face, scalp, and palmoplantar surfaces were unaffected.