Further evidence for the T-cell nature of the atypical mononuclear cells in mycosis fungoides.

It is well known that in some cases of mycosis fungoides the lymph nodes contain atypical mononuclear cells with a characteristic electron-microscopic morphology, first described in skin lesions of mycosis fungoides. Because it has been shown, that these cells have T-cell membrane characteristics the question can be raised, if these cells have other properties of T cells. One of these is a preferential localization in the T-cell dependent regions (paracortical areas) of the lymph node. In this paper we present a study of dermatopathic lymph nodes from four patients with mycosis fungoides (plaque stage). The lymph nodes of these patients contained atypical mononuclear cells in the paracortical areas only, and not in the follicles or medulla. In one of the patients we could demonstrate the migration of these cells through the epitheloid venules into the paracortical area. Our observations give further evidence of the T-cell nature of the atypical mononuclear cells in mycosis fungoides.