Cutaneous Lymphoma

Cutaneous

Primary cutaneous lymphomas are those malignant lymphoproliferative disorders of B or T lymphocytes, whose first manifestation is the presence of human skin lesions without extracutaneous disease occurs at the time of diagnosis, being observed nodal or visceral disease course. The skin is the 2nd location (after the location gastrointestinal) in frequency of primary extranodal lymphomas. Unlike non-Hodgkin lymphomas ganglion that are mostly B-cell lymphomas, 75% of primary lymphomas are T-cell lymphomas, with two thirds of cases mycosis fungoides and Sezary syndrome. The incidence of cutaneous T has progressively increased and is currently of 6.4 cases per million. The incidence increases significantly with age, with an average age of diagnosis 50 years and is 4 times more frequent over 70 years.

Pathogenesis Of Cutaneous Lymphomas

There are several pathogenic mechanisms for the development of cutaneous lymphomas including chromosomal translocations, alterations in tumor suppressor genes (bcl2), immunological and external factors such as viral infections. Skin contains some characteristics suitable for the development of lymphomas, it is estimated that normal skin contains approximately 1 million cells per cubic centimeter T, consequently the skin is an important lymphoid organ and containing eldoble of T cells from peripheral blood. Skin, like the lymph node has several compartments in which are distributed T and B lymphocytes Usually T cells are distributed mostly in the epidermis, papillary dermis, superficial vascular plexus, perianexialmente and the deep portion of subcutaneous fat (in the ganglion are distributed in the paracortex and medulla). B lymphocytes are in the middle and deep dermis, deep vascular plexus and fat tissue (in the ganglion are distributed in the cortex and medulla), this partitioning is accompanied by a cytokine secretion pattern characteristic. This distribution of lymphocyte subpopulations gives a histological pattern for different forms of primary cutaneous lymphoma and cutaneous mycosis fungoides type presented a histological pattern epidermotropo while B and T lymphomas, mycosis fungoides not have a diffuse pattern without epidermotropism or perivascular.

Diagnosis Of Primary Cutaneous Lymphomas

Making the diagnosis of cutaneous lymphoma requires a wide range of clinical and pathological studies to correctly classify the sick. These studies include clinical examination, radiological, histological and molecular studies. Patients with suspected primary cutaneous lymphoma should undergo a thorough clinical examination including thoraco-abdominal radiographic studies (CXR, CT chest and abdomen) and bone marrow examination, all in connection with the diagnosis of suspicion . Histological studies should include study of hematoxylin and eosin, PAS and Giemsa. They also performed immunohistochemical studies with antibodies against antigens characteristic of different cell subpopulations of lymphocytes, macrophages, and dendritic interdigitating cells. Gene rearrangement analysis by Southern blot techniques and PCR (PCR / DGGE) of the genes of the T cell receptor (TCR) and immunoglobulins are useful techniques in the study of cutaneous since they can provide data on the presence of clones of lymphocytes.

Classification Of Cutaneous Lymphomas

There are several ways to classify lymphomas, has recently reached a consensus classification that groups the classification of the WHO and EORTC ( Blood 2005) which replaces the previous, independent of the WHO and EORTC .

Cutaneous T-cell lymphomas

Mycosis Fungoides

It is the most common form of primary cutaneous lymphoma, is a cutaneous T-cell lymphoma, often epidermotropo characterized by a proliferation of T lymphocytes with small or medium-sized cerebriform nucleus. It was first described in 1806 by Alibert receiving its name from the appearance of the lesions fungoides cutaneous tumor. It has an incidence of 0.29 cases / 100,000 population per year, with a peak age between 55 and 60. The clinical manifestations are very varibles from single lesions to erythroderma.

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