Looks Like Psoriasis,but it's not
Cutaneous T-Cell Lymphoma, or CTCL for short, often appears as persistent scaly red patches which look quite similar to psoriasis. To make diagnosis more confusing, a skin biopsy of a lesion of CTCL may not show the disease until a patient has had the condition for up to 7 years. Another name for the most common type of CTCL is mycosis fungoides but this name is slowly fading from use since it sounds like it pertains to a fungal infection and not a malignancy.How it Differs from Psoriasis
In the long run, lesions of CTCL often evolve from a flat or patch stage to a raised or plaque stage and finally to large lesions called tumor stage. Lymph nodes can be enlarged and malignant white blood cells called Sezary cells can be found in the bloodstream.Treatment of CTCL
Early stages of CTCL often respond to the same types of treatments as psoriasis such as topical steroids or phototherapy. Later stages may need chemotherapy or a CTCL-specific retinoid drug called targretin.Treatment of Advanced Cases of CTCL
Generally speaking, advanced cases of CTCL are more likley to be treated by an oncologist than a dermatologist. A form of phototherapy called extracorporeal photopheresis where blood is removed from the body and exposed to ultraviolet light can be used in advanced cases as well as total body electron beam therapy, a type of radiation therapy. Advanced cases of CTCL which do not respond to any of these therapies are treated with even newer medications. An interesting drug called Ontak is approved for use of CTCL. Ontak is made by fusing diptheria toxin to the cytokine IL-2. When it binds to the IL-2 receptors present on CTCL cells, they die. Zolina is used for CTCL when other treatments have already failed. It alters the malignant cells' DNA metabolism. Both Ontak and Zolina have been associated with severe side effects.What Should I do with This Information?
If you have a stubborn rash, which is somewhat atypical for psoriasis and it has not responded well to treatment, it may be worthwhile to consider a skin biopsy of a lesion to determine if features of CTCL or psoriasis are present. In many cases, the rash of CTCL may preceed a definitive biopsy diagnosis by several years, hence in some patients repeated serial skin biopsies over many years may be required to confirm a diagnosis of CTCL.
Source: Kerdel FA, Jiminez-Acosta F. Dermatology Just the Facts. McGraw-Hill. New York 2005. pages 276-277.
