This 57-year -old man had a lifelong history of keratoderma involving the palms and soles. He had numerous, non-inflammatory, "cup-shaped" hyperkeratotic lesions, diffusely involving the palms and soles. Palmoplantar keratoderma has variable presentations and variable inheritance patterns. This patient had an isolated condition, without features of one of the syndromes, and no family history. The clinican had arsenic exposure on his differential. The histology here is fairly typical, showing hypergranulosis with overlying mounds of orthokeratosis.
Histologic sections of skin show mounds of orthokeratosis overlying a small epidermal dell. There is mild epidermal acanthosis. The adjacent epidermis more closely resembles normal acral skin.