Cutaneous malignant lymphomas: Update 2006

Abstract

Cutaneous lymphomas represent a unique group of lymphomas and are the second most frequent extranodal lymphomas. As with other neoplasias, the pathogenesis is based mainly on a stepwise accumulation of mutations of suppressor genes and oncogenes caused by genetic, environmental or infectious factors. The diagnostic work-up includes clinical, histological, imaging and hematological investigations and in many cases immunohistochemical and molecular biological analyses. The current WHO/EORTC classification of cutaneous lymphomas differentiates "mature T-cell and NK-cell lymphomas", "mature B-cell lymphomas" and "immature hematopoietic malignancies", their variants and subgroups. It is compatible with the WHO classification for neoplasias of the hematopoietic and lymphoid tissue and respects the organ-specific peculiarities of primary cutaneous lymphomas. The assignment of the various types of cutaneous lymphomas into prognostic categories (pre-lymphomatous "abortive" disorders; definite malignant lymphomas of low-grade malignancy; definite malignant lymphomas of high-grade malignancy) provides essential information on the biological behavior and allows an appropriate planning of the therapeutic strategy, which may be topical or systemic and aggressive or non-aggressive. Besides the classical options for therapy, there are new and "experimental" strategies, the efficacy of which has to be studied in clinical trials.

Immunohistochemical profile of multicentric cutaneous epitheliotropic T-cell lymphoma with generalised lymphadenopathy in a Holstein-Friesian cow: a case report

“…However, the characteristic localisation of the first skin lesions, which appeared along lymphatic vessels in the reported study, may suggest an infectious or allergenic agent as the precipitating factor. To date, the exact factor that causes sporadic cutaneous lymphoma in cattle has not yet been identified but the tumour most likely results from a multifactorial and multi-step process as observed in humans (Burg et al 2006). Additionally, the overexpression of MHC class II observed in accompanying APCs may indicate the presence of tumour-promoting chronic inflammation or the tumour immune surveillance process (Swann and Smyth 2007).…”

“…Within the group of PCLs, distinct types of cutaneous T-cell lymphomas (CTCL) and cutaneous B-cell lymphomas (CBCL) can be distinguished (Willemze and Dreyling 2010). Cutaneous T-cell lymphoma in humans, most commonly seen as mycosis fungoides (MF), is a relatively common clonal expansion of T helper cells and, more rarely, T suppressor/killer cells or NK cells (Burg et al 2006). Cutaneous lymphomas reported in most domestic and many animals in the wild are usually divided into epitheliotropic and non-epitheliotropic categories (Gross et al 2005;Valli 2007).…”

“…Primary cutaneous lymphomas (PCLs) in humans are defined according to the World Health Organization and European Organization for the Research and Treatment of Cancer Classification as non-Hodgkin's lymphomas that present on the skin with no evidence of extracutaneous disease at least six months after diagnosis and disease progression (Burg et al 2006;Willemze and Dreyling 2010). Within the group of PCLs, distinct types of cutaneous T-cell lymphomas (CTCL) and cutaneous B-cell lymphomas (CBCL) can be distinguished (Willemze and Dreyling 2010).…”

“…The expression of CD4 and CD8 is variable in cats (Valli 2007). The pathogenesis of cutaneous lymphomas most likely involves multiple steps, has a multifactorial nature and starts as a hyper-reactive, inflammatory process due to various stimuli that may be genetic (numerical and structural chromosomal abnormalities), environmental, infectious (herpes-and retroviruses, bacteria, chlamydia) or immunological (vaccination or allergen hypersensitivity, drugs or arthropod reactions) (Burg et al 2006). MHC class II molecules play a pivotal role in the induction and regulation of an antigen-specific immune response.…”

The History of Lymphoma Classifications with Special Consideration of Cutaneous Lymphomas

“…According to Burg et al [160], the current WHO-EORTC classification represents only a working basis for a further increase in knowledge through prospective gene expression pattern analyses, epigenetic and proteomic analyses also influencing the classification of PCL [160][161][162].…”