RESUMEN
Non-melanoma skin cancer (NMSC) is the most common type of neoplasm affecting Caucasian individuals, with squamous-cell carcinoma (cSCC) being the second most common type of NMSC after basal-cell carcinoma. The immunohistochemical study of cSCC is of particular importance, especially for the diagnosis of its rare forms, for which accurate and early diagnosis is crucial for survival. In the present review of the literature, the potentially significant value of immunohistochemical markers were highlighted to more accurately assess the biological behaviour, the prognosis of cSCC and to optimize case management. The immunohistochemical markers were classified from a pathophysiological point of view in order to present the mechanism by which carcinogenesis occurs with its subsequent evolution and therefore, to develop a more accurate novel risk staging criteria for this type of neoplasm.