||Histologically, the epidermis shows a disorderly arrangement with hyperkeratosis, parakeratosis, dyskeratosis, and mild to moderate pleomorphism of the nuclei of the cells of the stratum malpighii. While solar keratoses may develop into squamous cell carcinoma, the tumor that develops is usually less malignant than the usual squamous cell carcinoma, which arises de novo.
Under low magnification, the stacked keratin squames have produced a keratin or cutaneous horn. The underlying epithelium is thickened with parakeratosis. H&E 39 x.