[Lymphomatoid papulosis]

Abstract

Lymphomatoid papulosis is a distinct entity in which recurring crops of haemorragic and necrotic papules display a cytologically malignant infiltrate. The aberrent cell is now generally accepted to be an active T helper phenotype. The expression of Ki-1 (CD30) on a significant portion of the infiltrating cells characterizes lymphomatoid papulosis and relates this disorder with Hodgkin's disease, mycosis fungoides and anaplasic T cell lymphoma which may be associated in 10 to 20% of lymphomatoid papulosis. The categorization of this disease as a benign disorder versus lymphoma remains controversial. Studies of T cell receptor gene rearrangement demonstrate clonality in many cases. So, this monoclonal population could have a malignant transformation induced by a triggering stimulus such as genetic translocation, or viral infection. Finally, recent opinions consider that lymphomatoid papulosis and Ki-1 (CD30) lymphomas are different parts of a clinical and histological spectrum constituted by cutaneous Ki-1 lymphoid infiltrates.