Lymphoproliferative skin diseases: causes, symptoms, diagnosis, treatment

Diagnostic evaluation of benign and malignant lymphoproliferative skin diseases presents a very difficult task for the pathomorphologist. In recent decades, significant progress has been made in this direction, related to the success of 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). As a basis for the morphological evaluation of nosological forms, the authors took the cytological characteristics of the lymphocyte in accordance with the stages of its sequential development from the stem cell to the memory cells and its localization in the normal lymph node. However, from the nosological forms directly encountered in the skin, the Kiel classification contains only mushroom-like mycosis and Cesari syndrome.

To some extent combine 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 cellular proliferation, which allows to determine the maturity of cellular elements.

An important aspect is the determination of the phenotypic characteristic of skin lymphomas using immunological markers typical of 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 that occur in the skin, in particular the variant of fungal mycosis in the form of granulomatous folded skin, lymphomatoid papulosis, systemic angioendothelioma (angiotropic lymphoma), syringolymphoid hyperplasia with alopecia and a number of other processes , whose belonging to the true lymphomas of the skin is not shared by all.

Thus, when formulating classifications of primary lymphomas of the skin, there is a tendency to combine the basic morphological characteristics characteristic of cells of the lymph node, with immunological and genotypic features of lymphocytes from the 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 classifications of nodal lymphomas, supplementing them in accordance with the organ-specific features of nosological forms peculiar to the skin. This approach was used in the classification of REAL (Revised European American Lymphoma Classification, 1994), WHO Classification (1997), EORTC (European Organization for Research and Treatment of Cancer, 1997).

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