Langerhans cells in various benign and malignant pigment-cell lesions of the skin

Abstract

We used immunohistochemistry to study Langerhans cells (LCs) and the composition of the dermal inflammatory infiltrate both in normal skin and in biopsies from various benign and malignant pigment-cell lesions. In normal skin and most benign pigment-cell lesions, epidermal LCs are regularly distributed. OKT6-Positive cells outnumber the OKIa-positive cells. The inconspicuous dermal infiltrate studied in these biopsies was composed of helper and suppressor/cytotoxic T cells and some dermal LCs. More epidermal LCs with an abnormal cytologic presentation were found in a halo naevus and in the radial growth part of primary malignant melanomas. This finding was associated with a dermal infiltrate composed of suppressor/cytotoxic T cells, suggesting a defense mechanism of the host towards abnormal melanocytes. Epidermal LCs were rare in the central part of the biopsies which showed a primary malignant melanoma in its vertical growth. A dermal inflammatory infiltrate was absent in that area. These findings are interpreted as the morphologic expression of a damaged immune system.

Langerhans cells and melanocytes share similar morphologic features under in vivo reflectance confocal microscopy: A?challenge for melanoma diagnosis

“…Similar findings of variations of LC density and distribution in the epidermis overlying in-situ and thin melanomas vs. “deeply invasive” melanomas were confirmed by Toriyama and colleagues 22 . Facchetti et al examined two melanoma cases with a peripheral radial growth and a central vertical growth 20 . They observed increased number of epidermal LC in periphery of the biopsy, while almost complete disappearance of epidermal LC in the vertical growth part of the lesion 20 .…”

“…LC have been observed in many benign and malignant tumors. 16–20 . Furthermore, alteration in density, distribution and morphology of LC have been reported with tumor progression 19–23 .…”

Advances in the immunobiology of the skin. Implications for cutaneous malignancies

“…The role of the cutaneous immune system in melanoma pathogenesis is even less well understood. Histologic studies show that epidermal Langerhans cells are rare in the central portion of malignant melanoma biopsies, whereas a normal distribution of Langerhans cells was found in the epidermis overlying benign nevi (77). This result suggests that damage to the cutaneous immune system may be involved in melanoma growth.…”

Tissue-resident dendritic cells and diseases involving dendritic cell malfunction

“…The number of LCs is increased in benign skin lesions, whereas in malignant tumors LCs is not only markedly reduced or absent but also grossly stunted and deformed in outline [ 148 ]. Because the growth of a primary malignant melanoma is vertical, epidermal LCs are rare in the central part of the tumor [ 149 ]. Patients with early stage breast cancer have significantly higher proportion of apoptotic blood DCs as compared to healthy volunteers [ 150 ].…”