Multilobated cutaneous T cell lymphoma. Report of two cases resembling Crosti's reticulosis.

2 middle-aged men are described with slowly progressive papular and nodular lesions, limited to the skin of the back. Clinically and histologically both resembled Crosti's reticulosis ('réticulo-histiocytome du dos de l'adulte'). It was determined by electron microscopic, enzyme cytochemical and immunological studies that the 'histiocyte' component, which was derived from T lymphocytes, consisted of blast-like cells with characteristic multilobated nuclei with nucleoli in marginal position. For this type of lymphoma, which may have been described previously as lymphocytoma cutis or reticulum cell sarcoma, the term 'multilobated cutaneous T cell lymphoma' is proposed. According to its slowly progressive clinical course it may be classified as a malignant lymphoma of low grade malignancy.