In this type of cancer, the white blood cells are responsible for the disease. The T-lymphocytes (T-helper cells) develop in an uncontrollable way and infiltrate into the epidermal layer of the skin, and cause lesions mostly situated in the trunk. After some time the lesions transform into palpable plaques with defined edges and then into mushroom shaped tumors. In the end, the tumor progresses into the lymph nodes and then spreads to other parts of the body. The internal organs are affected in 20-30% of the patients who have this disease.

A particular form of the cutaneous T-cell lymphoma is the S'zary syndrome. Signs of this disease are: an overall redness of the skin, small bumpy tumors, and the skin is atrophic. At physical examination doctors see that the lymph nodes have swollen and discover an increased number of malign lymphocytes.

The disease affects mostly men than women, at the age of 55 or 60; annually the new cases discovered in US are more than 500 and there are registered 100-200 deaths. The cutaneous T-cell lymphoma is considered to be a rare affection, in US, the annual incidence being of about .29 cases per 100,000 persons.

Scientist first suspected that pesticides and chemicals caused the disease, but after performing researches they believe that a virus leads to cutaneous T-cell lymphoma. This hypothesis is still not 100% confirmed.

Generally patients go to the doctor because they have an itchy red skin zone that bothers them for some time. If the disease has already spread outside the skin, the patient might feel its lymph nodes swollen.

Usually, the itchy skin patches can be easily mistaken for other skin diseases, like eczema, psoriasis, and contact dermatitis. Doctors prescribe a corticosteroid treatment and in some cases the skin lesions respond favorably to it, so the patient carries this disease a few years more until the real affection is discovered; then it is too late to treat it.

If a doctor is inspired to perform a biopsy of the affected area he might diagnose the disease earlier and treatment could be rapidly instituted. When studying the tissue there can be seen abnormal cells, and by performing a Southern blot analysis there will be observed changes of the gene that encodes the T-cell receptors. Biopsy is the most accurate way of diagnosing cutaneous T-cell lymphoma that is why all doctors must request it when suspecting such a disease.