Cutaneous T-Cell Lymphoma

98


Cutaneous T-Cell Lymphoma




• Primary cutaneous lymphomas present in the skin without evidence of extracutaneous disease at the time of diagnosis.


• Secondary cutaneous lymphomas are skin manifestations of systemic (nodal) lymphomas and will not be discussed (see oncology texts).


• Primary cutaneous lymphomas may be of T–cell origin (75–80%) or B–cell origin (20–25%) and are termed CTCL and CBCL, respectively.


• The term CTCL will be used herein to describe the heterogeneous group of primary cutaneous lymphomas composed of neoplastic T cells or natural killer (NK) cells (Table 98.1).



• As different types of CTCLs, CBCLs, and even secondary cutaneous lymphomas may present with similar clinical and histopathological features, it is imperative to combine clinical and staging data with histologic, immunophenotypic, and genetic data before making a definitive diagnosis (classification).


• Immunophenotyping, as determined from immunohistochemical studies done on skin biopsy specimens, can help distinguish between a T-cell vs. an NK-cell vs. a B-cell lymphoma and can aid in subtyping.


• T-cell receptor (TCR) gene rearrangement analysis, either with Southern blot analysis or by more sensitive PCR-based techniques, is useful in detecting the presence or absence of a clonal T-cell population in skin biopsy specimens.


• The presence of a clonal T-cell population cannot be used as an absolute criterion of malignancy, as several benign conditions may also demonstrate clonality (e.g. pityriasis lichenoides et varioliformis acuta, lichen planus, pigmented purpuric dermatosis, lichen sclerosus, and some pseudolymphomas).


• An approach to the evaluation of a patient with suspected CTCL is presented in Fig. 98.1.


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Apr 22, 2016 | Posted by in Dermatology | Comments Off on Cutaneous T-Cell Lymphoma

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