Lymphomatoid papulosis. Histologic and immunohistochemical studies in a patient with a scaly pigmented eruption.

A patient with lymphomatoid papulosis type A showed a peculiar, scaly pigmented eruption on the broad skin areas as well as papulonodular lesions. Large atypical cells characteristic of the infiltrate of the disease were observed not only in the dermal infiltrate of papular lesions, but also in the perivascular infiltrate of the scaly pigmented lesions, indicating that the latter was one of the skin manifestations of lymphomatoid papulosis. Immunohistochemical studies showed that these atypical cells expressed Ki-1 and cellular activation-associated antigens such as HLA-DR, Tac, and T9, but were not reactive with T-cell specific antibodies Leu-1, Leu-3a, and Leu-2a.