Lymphomatoid papulosis. Case report providing evidence for a monocyte–macrophage origin of the atypical cells

A patient with "classical" lymphomatoid papulosis is described in whom self-healing tumorous lesions occurred. Histologic, immunologic, enzyme histochemical and ultrastructural studies were performed. The atypical cells were found to be of monocyte-macrophage origin. The infiltrate also contained a variable number of suppressor-cytotoxic T-lymphocytes, depending on the stage of the tumorous lesions. The number of IgA positive B-lymphocytes in the peripheral blood was increased. The findings indicate that "classical" lymphomatoid papulosis is not a cutaneous T-cell lymphoma, but is the expression of an abnormal, immune reaction in the skin.