Lymphoproliferative skin diseases: causes, symptoms, diagnosis, treatment

Diagnostic evaluation of benign and malignant lymphoproliferative skin diseases is a very difficult task for a pathologist. In recent decades, significant progress has been made in this area due to advances in immunology. The morphological basis for the classification of lymphoproliferative skin diseases is laid down in the Kiel Classification (1974) and its subsequent modifications (1978, 1988). The authors based the morphological evaluation of nosological forms on the cytological characteristics of the lymphocyte in accordance with the stages of its sequential development from a stem cell to memory cells and its localization in a normal lymph node. However, of the nosological forms directly encountered in the skin, the Kiel Classification contains only mycosis fungoides and Sezary syndrome.

In order to combine to some extent the clinical and pathomorphological criteria, the classification of malignant skin lymphomas should include a wide range of clinical manifestations taking into account the morphological features of the cell proliferation, which allows determining the degree of maturity of the cellular elements.

An important aspect is the determination of the phenotypic characteristics of skin lymphomas using immunological markers typical for certain nosological forms. To differentiate benign and malignant processes, it is also necessary to take into account changes in the genome of T- or B-lymphocyte receptors, the so-called genotyping.

G. Burg et al. (1994) additionally included in the Kiel classification of non-Hodgkin's lymphomas a large group of rare lymphoproliferative diseases occurring in the skin, in particular a variant of mycosis fungoides in the form of granulomatous folded skin, lymphomatoid papulosis, systemic angioendotheliomatosis (angiotropic lymphoma), syringolymphoid hyperplasia with alopecia and a number of other processes, the belonging of which to true lymphomas of the skin is not shared by all.

Thus, when formulating classifications of primary skin lymphomas, there is a tendency to combine the basic morphological characteristics inherent in lymph node cells with the immunological and genotypic features of lymphocytes from foci of proliferation in the skin.

This process requires certain compromises. As noted by G. Burg et al. (2000), in order to find mutual understanding with pathologists and hemato-oncologists, it is necessary to use a single terminology and adapt the classification of nodal lymphomas, supplementing them in accordance with the organ-specific features of nosological forms inherent in the skin. A similar approach was used in the REAL classification (Revised European American Lymphoma Classification, 1994), WHO Classification (1997), EORTC (European Organization for Research and Treatment of Cancer, 1997).

[ 1 ]