Palmoplantar hyperkeratosis (HP_0000972) is abnormal thickening of the skin localized to the palm of the hand and the sole of the foot. Also known as: Hyperkeratosis of palms and soles, Hyperkeratosis of the palms and soles, Palmoplantar keratoses, Palmoplantar keratosis, Thick palms and soles, Thickened palms and soles, Thickening of the outer layer of the skin of the palms and soles.