Punctate hyperkeratosis of the palms and soles: An ultrastructural study

Punctate hyperkeratosis of the palms and soles is an uncommon autosomal dominant condition. We report a 65-year-old man with this condition and review the literature. With electron microscopy, we have examined both clinically affected and adjacent clinically unaffected palmar skin. The only ultrastructural differences noted were a thicker keratin layer and hypertrophic nucleoli in the basal cell layer and stratum spinosum in the clinically affected skin. This nucleolar hypertrophy suggests that there may be increased metabolic activity in the clinically affected skin which is contributing to the abnormal keratinization.