Cutaneous Lymphoma

Definition of cutaneous lymphoma

Cutaneous lymphoma is inserted among the rare neoplasms of lymphatic tissue, and manifests itself with the abnormal development of T cells (a type of white blood cells) at the level of the skin.

Cutaneous lymphoma is defined as a monoclonal proliferation of lymphatic cells that occurs at the skin level : if the skin is the onset locus ( primary cutaneous lymphoma ), it does not mean that the tumor cannot expand into other tissues, indeed, in most in some cases, cutaneous lymphoma evolves into other districts causing substantial damage. If the skin was affected only secondarily by the neoplasm, the disease takes the name of secondary cutaneous lymphoma .

Cutaneous lymphomas occur mainly in senescence, especially in the male (it is estimated that 3 women are affected every 9 males).

Classification

Among the various primitive forms of cutaneous lymphoma, we recall Sèzary's syndrome and mycosis fungoides (to which an article will be dedicated), which are distinguished, essentially, by the clinical profile. Nevertheless, there are other forms of cutaneous lymphoma, which differ in aetiology, clinical, symptomatology and degree of malignancy. In fact, cutaneous lymphoma represents a heterogeneous disease from the clinical, etiopathological, and evolutionary point of view; moreover, patients with cutaneous lymphoma respond in different and subjective ways to treatment therapies.

Cutaneous lymphomas can be classified according to the prognostic implications and to the cells involved:

T cell involvement

• Sezary syndrome (severe prognosis)
• peripheral T-cell lymphoma (severe prognosis)
• mycosis fungoides (good prognosis): the most frequent form that occurs in half of the subjects suffering from 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)

B lymphocyte involvement

• cutaneous lymphoma of the legs affecting large cell B lymphocytes (variable outcome)
• cutaneous and marginal follicular lymphomas (good prognosis)
• NK blastic lymphomas (severe prognosis)

The aforementioned classification of cutaneous lymphomas is only one model; in fact, precisely because the disease involves obvious differentiations in its sub-categories (from the clinical, pathological, etiological and phenotypic point of view) many cataloging of the various forms of cutaneous lymphoma have been carried out.

Symptoms

Most cutaneous lymphomas involving B cells present 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 has no extra-cutaneous lesions and there is an expression of B-lymphocyte antigens by tumor cells. Furthermore, there is a monoclonal restriction of immunoglobulins (plasma and surface). The lesions mainly affect the neck, the head, the trunk.

Even if the lymphomas affect T cells, the skin is certainly the favorite target; the disease can progress slowly or rapidly, spreading through the various skin areas. In the second case, most therapies have a poor prognosis.

Primitive type B lymphomas usually manifest 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 implicated in the onset of cutaneous lymphoma .

The theory of viral infectious agents deserves further study: the genome of HTLV-1 viruses (human T lymphocyte virus, Anglo-Saxon acronym of Human T-lymphotropic virus) and EBV virus (Epstein-Barr virus, already analyzed in the article "Burkitt's lymphoma", as responsible for the neoplasm) seems to mix with the lymphocytic genome. This theory has been considered by many researchers, but other authors contest it and consider more plausible the hypothesis that 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, environmental allergens and work activities (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 results in the majority of subjects affected by primitive cutaneous forms, both involving T lymphocytes and those involving type B. The chemotherapeutic treatments for the resolution of lymphomas with a high degree of malignancy, unfortunately, do not they foresee great probability of resolving outcome.

In addition to chemotherapy, patients with cutaneous lymphoma may undergo radiotherapy, PUVA therapy, and extracorporeal photophoresis; the latter therapy, which modulates the autoimmune system, involves taking lymphocytes, which are re-inserted into the body after being irradiated with photoactive substances. Extracorporeal photophoresis appears to improve the prognosis of some forms of cutaneous lymphoma.

Cutaneous lymphomas in general are still under study: the researchers aim to interpret 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 ...