Composite keratohyaline granules in striate keratoderma

The gross, light microscopic, and ultrastructural findings in a 55 year old man was striate keratoderma are presented. There was no family history of the disease. The lesions developed in his late teens and early adult years, and consisted of progressively worsening, raised, hyperkeratotic, linear p laques on the palm and volar surface of the third and fifth fingers bilater ally. There were also painful callosities on both heels, and thick, raised plaques on the heels and lateral plantar surfaces. The epidermis was papill omatous and acanthotic, with marked orthokeratosis, minimal parakeratosis, and a very thickened granular layer. No epidermolysis was seen. Electron mi croscopy showed increased tonofibrils in the stratum spinosum arranged in w avy, parallel bundles and a granular layer in which normal Odland bodies we re present. However, the keratohyaline granules were large, with rounded bo rders and a striped, alternating, dark and light content characteristic of composite granules. There was diminished contact of the granules with tonof ibrils. The transition to the stratum corneum was abrupt. The ultrastructur al and genetic features of keratodermas, with special emphasis on the stria te type, are reviewed.