Definition of cutaneous lymphoma
Cutaneous lymphoma is one of the rare cancers of the lymphatic tissue, and occurs with the abnormal development of T cells (a type of white blood cell) in the skin.
Cutaneous lymphoma is termed a monoclonal proliferation of lymphatic cells that occurs in the skin: if the skin represents the locus of onset (primary cutaneous lymphoma), does not mean that the tumor cannot expand into other tissues, on the contrary, in most cases, the cutaneous lymphoma evolves in other areas causing substantial damage. If the skin is only secondarily affected by the neoplasm, the disease is called secondary cutaneous lymphoma.
Cutaneous lymphomas occur mainly in senescence, especially in males (it is estimated that 3 women out of 9 males are affected).
Classification
Among the various primitive forms of cutaneous lymphoma, the Sèzary syndrome and mycosis fungoides (to which an article will be dedicated) are mentioned, which are substantially distinguished by the clinical profile. Nevertheless, there are other forms of cutaneous lymphoma, which differ in etiology, clinic, symptoms and degree of malignancy. In fact, cutaneous lymphoma represents a heterogeneous disease from a clinical, etiopathological and evolutionary point of view; moreover, cutaneous lymphoma patients respond differently and subjectively to therapeutic treatments.
Cutaneous lymphomas can be classified according to the prognostic implications and the cells involved:
Involvement of T cells
- Sezary syndrome (severe prognosis)
- peripheral T-cell lymphoma (severe prognosis)
- mycosis fungoides (good prognosis): the most frequent form that occurs in half of subjects with cutaneous lymphoma
- cutaneous T-cell lymphoma (good prognosis)
- panniculitis-like subcutaneous T-cell lymphoma (variable outcome)
- pleomorphic T-cell lymphoma (variable outcome)
- cutaneous T / NK cell lymphomas (variable outcome)
Involvement of B lymphocytes
- cutaneous leg lymphomas affecting large cell B lymphocytes (variable outcome)
- cutaneous and marginal follicular lymphomas (good prognosis)
- blastic NK lymphomas (severe prognosis)
The above classification of cutaneous lymphomas is only a model; in fact, precisely because the disease involves evident differentiations in its sub-categories (from a clinical, pathological, etiological and phenotypic point of view), many catalogs of the various forms of cutaneous lymphoma have been made.
Symptoms
Most cutaneous lymphomas affecting the B cells, it has a fairly homogeneous clinical course: chronic course, good prognosis, positive response to therapies (surgery, radiotherapy, chemotherapy), low mortality rate. At the time of diagnosis, in general, the lymphoma does not present extra-cutaneous lesions and there is an expression of the B-lymphocyte antigens by the tumor cells. Furthermore, there is a monoclonal restriction of immunoglobulins (plasma and superficial). they mainly affect the neck, head, trunk.
Even if the lymphomas affect the T cells, the skin is certainly the favored target; the disease can progress slowly or rapidly, spreading to various skin areas. In the second case, most therapies have a poor prognosis.
Primary type B lymphomas usually have red nodules and papules associated with ulcers.
In general, most cutaneous lymphomas present with desquamative and erythematous plaques, nodular lesions and ulcerations.
Causes
The etiopathological picture of cutaneous lymphomas is uncertain, but there are some hypotheses according to which oncogenes, viral infectious agents, cytokines, antigens derived from the environment, associated with work activities, represent the factors potentially involved in the onset of cutaneous lymphoma .
There theory of viral infectious agents deserves further study: the genome of HTLV-1 viruses (human T lymphocyte virus, English acronym of Human T-lymphotropic virus) and EBV virus (Epstein-Barr virus, already analyzed in the "Burkitt lymphoma" article, as responsible for the neoplasm) appears to mix with the lymphocyte genome. This theory has been considered by many researchers, but other authors contest it and consider more plausible the hypothesis according to which the production of cytokines and interleukins in the skin could favor various forms of abnormal proliferation of T lymphocytes.
As regards the possible correlation with oncogenes, with environmental allergens and with work activity (eg exposure to industrial waste products, hydrocarbons, aromatic substances, etc.), there is still no evidence that these factors can directly affect in the formation of cutaneous lymphomas.
Therapies
The therapies are effective and give positive outcomes in the majority of subjects affected by primary skin forms, whether they affect T lymphocytes or type B. Chemotherapy treatments for the resolution of lymphomas with a high degree of malignancy, unfortunately, do not provide great probabilities of resolutive outcome.
In addition to chemotherapy, patients with cutaneous lymphoma can undergo radiotherapy, PUVA therapy, and extracorporeal photophoresis; this last therapy, which modulates the autoimmune system, involves the removal of lymphocytes, which are re-inserted into the body after being irradiated with photoactive substances. Extracorporeal photophoresis seems to improve the prognosis of some forms of cutaneous lymphoma.
Cutaneous lymphomas in general are still being studied: the researchers set themselves the goal of interpreting the complicated molecular mechanisms that cause them, in order to open new therapeutic avenues and innovative treatments to completely eradicate all the various types of cutaneous lymphoma.
Summary
To fix the concepts ...
Cutaneous lymphoma: a rare neoplasm of the lymphatic tissue that involves the abnormal proliferation of T lymphocytes in the skin.
Classification
Primary cutaneous lymphoma
Secondary cutaneous lymphoma
Skin lymphoma affecting T cells (e.g. Sezary syndrome and mycosis fungoides)
Cutaneous lymphoma affecting B lymphocytes
Prognosis
It varies according to the type of lymphoma: good, severe, variable / unpredictable
Clinical course of cutaneous lymphomas (B lymphocytes)
Homogeneous clinical course: chronic course, good prognosis, positive response to therapies (surgery, radiotherapy, chemotherapy), low mortality rate
Clinical trend of cutaneous lymphoma T lymphocytes)
It affects the skin. Chronic slow (good prognosis) or rapid (little hope of survival) course
General symptoms
Desquamative and erythematous plaques, nodular lesions and ulcerations.
Causes
Hypothesis of predisposing factors: oncogenes, viral infectious agents (EBV virus and HTLV-1 virus), cytokines, antigens derived from the environment, work activities of the subject.
Possible therapies to fight cutaneous lymphomas
Chemotherapy, radiotherapy, PUVA therapy, and extracorporeal photophoresis.
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