ABSTRACT
The spectrum of cytotoxic lymphomas of the skin is heterogeneous and includes CD8þ T-cell, T=NK-cell, and NK-cell lymphomas as well as neoplasms related to myelomonocytic leukemia. As a common hallmark, the tumor cells display cytotoxic proteins. There is no widely accepted classification (and or even nomenclature) of this group of lymphomas. Immunophenotyping plays a crucial role in diagnosing cytotoxic lymphomas. Future developments will clarify, which forms of cytotoxic lymphoma in fact represent cytotoxic variants of well-established CL such as MF and which ones are distinct nosologic entities. In accordance with the basic principle
Table 1 Cytotoxic Lymphomas with Primary or Secondary Cutaneous Involvement
Primary cutaneous CD8þ cytotoxic lymphoma Epidermotropic forms MF-like hypo-or hyperpigmented types Aggressive type Sezary syndrome-like variant
Nonepidermotropic forms Nodular type
Extranodal NK=T-cell lymphoma Nasal type Subcutaneous panniculitis-like lymphoma Gamma=delta lymphoma Lymphoblastoid NK-cell lymphoma=leukemia CD4þ CD56þ blastic lymphoma=leukemia Aggressive T=NK cell lymphoma=leukemia
Werner Kempf, Dmitry V. Kazakov, Reinhard Dummer, and Gu¨nter Burg Department of Dermatology, University Hospital, Zu¨rich, Switzerland
The spectrum of cytotoxic lymphomas of the skin is heterogeneous and includes CD8þ T-cell, T=NK-cell, and NK-cell lymphomas as well as neoplasms related to myelomonocytic leukemia. As a common hallmark, the tumor cells display cytotoxic proteins. There is no widely accepted classification (and or even nomenclature) of this group of lymphomas. Immunophenotyping plays a crucial role in diagnosing cytotoxic lymphomas. Future developments will clarify, which forms of cytotoxic lymphoma in fact represent cytotoxic variants of well-established CL such as MF and which ones are distinct nosologic entities. In accordance with the basic principle
Table 1 Cytotoxic Lymphomas with Primary or Secondary Cutaneous Involvement
Primary cutaneous CD8þ cytotoxic lymphoma Epidermotropic forms MF-like hypo-or hyperpigmented types Aggressive type Sezary syndrome-like variant
Nonepidermotropic forms Nodular type
Extranodal NK=T-cell lymphoma Nasal type Subcutaneous panniculitis-like lymphoma Gamma=delta lymphoma Lymphoblastoid NK-cell lymphoma=leukemia CD4þ CD56þ blastic lymphoma=leukemia Aggressive T=NK cell lymphoma=leukemia
(WHO, REAL, and EORTC) to the aim of this chapter is to describe those forms of cytotoxic lympho-primary or secondary skin involvement which display distinct clinical, and immunophenotypic features (Table 1). It is essential to identify with a cytotoxic phenotype, since some forms exhibit an aggressive course which has therapeutic implications (1-4).
