Primary Cutaneous CD30 (KI-1) Positive Large Cell Lymphomas: Definition and Differential Diagnostic Aspects

Recent studies have suggested that primary cutaneous CD30 (Ki-1) positive T-large cell lymphomas represent a distinct type of cutaneous lymphoma with a favorable prognosis. Here the results of recent studies aimed to define this new type of cutaneous lymphoma more precisely are presented. The importance of differentiating these lymphomas from other CD30+ lymphoproliferative disorders that may occur in the skin is emphasized. Recent evidence suggesting that these primary cutaneous CD30+ large cell lymphomas are closely related to lymphomatoid papulosis is discussed.