Background and design: --Many investigators have applied immunohistologic analysis to skin biopsy specimens to distinguish cutaneous T-cell lymphoma (CTCL) from benign inflammatory diseases, such as psoriasis and dermatitis, which can clinically mimic early-stage CTCL. We studied the number and distribution of epidermal cells labeled with various monoclonal antibodies in normal skin and in psoriatic, dermatitic, and CTCL lesions by the immunoperoxidase technique.
Results: --Extensive staining of keratinocytes (KCs) with HLA-DR was seen in 27 of 41 patients with CTCL, but in only one of 14 patients with psoriasis and zero of 10 patients with dermatitis. CD2+ and CD3+ cells were present in the middle and upper epidermis of CTCL lesions in much greater numbers than in normal, dermatitic, and psoriatic skin. The percent epidermal area covered by CD1+ cells in psoriatic lesions (1.13%) and dermatitic lesions (1.65%) was significantly lower than that found in CTCL lesions (3.60%).
Conclusion: --Epidermal immunohistologic patterns using anti-CD1, anti-CD2, anti-CD3, and anti-HLA-DR antibodies have the potential to distinguish CTCL from psoriasis and dermatitis in clinically ambiguous cases.