Role of Lymphocytic Immunohistochemical Markers in Early Diagnosis of Peripheral T-Cell Lymphoma of the Skin – Mycosis Fungoides

Abstract

Background: Mycosis fungoides (MF) is the most common type of primary cutaneous peripheral T-cell lymphoma. The diagnosis of early-stage MF is challenging due to its clinical and histological resemblance to a number of benign inflammatory dermatoses. Often an immunohistochemical phenotyping is required for the diagnosis.Purpose: To assess the diagnostic value of a panel of seven lymphocytic immunohistochemical markers (CD3; CD20; CD4; CD8; CD45RO; CD30; Bcl2) in the early diagnosis of MF.Material/Methods: Biopsies from 30 patients with confirmed early-stage MF were stained with lymphocytic markers: CD3; CD20; CD4; CD8; CD45RO; CD30; Bcl2. The epidermal and dermal expression in this group was compared with a control group of 30 cases of benign inflammatory dermatoses, which clinically resemble MF.Results: A statistically significant difference was found in the expression of CD3, CD4, CD8, CD45RO and Bcl2 in the epidermis between the two groups and the expression of CD3, CD4, CD8, CD45RO and CD30 in the dermal infiltrate. There was no statistically significant difference in the expression of CD20 and Bcl2 in the dermal infiltrate between the two groups.Conclusions: There is no single marker that has enough sensitivity and specificity to be used independently for the diagnosis of MF. High epidermal expression of CD3, CD4, and CD45RO by infiltrating lymphocytes is diagnostic for MF. The most sensitive marker for MF is the CD4/ CD8 ratio in the dermal infltrate; it takes into account the statistically different expression of CD4 and CD8 in both groups.