Cutaneous T-Cell Lymphoma in a Woman With Pruritic, Erythematous Rash

For several weeks, a 78-year-old woman had an intensely pruritic, diffuse, raised, slightly scaly, erythematous rash that persisted despite the use of several over-the-counter topical medications (such as hydrocortisone and clotrimazole cream). Since her last visit about 3 months earlier for a blood pressure reading, she had been well except for 2 episodes of night sweats. For several years, she had been taking levothyroxine and reserpine/hydrochlorothiazide; about 6 months ago, valsartan/ hydrochlorothiazide had been prescribed. A potassium hydroxide preparation of scrapings from the rash showed no hyphae. Results of a punch biopsy revealed subacute eczematous dermatitis without vasculitis. The patient was given oral prednisone, 40 mg/d. Within a week, the rash and pruritus had nearly resolved, and the prednisone dosage was gradually tapered. Two weeks later, the rash recurred. The prednisone regimen was restarted and tapered more slowly, and triamcinolone cream 0.1% was added. About 1 month later, the rash returned. A second biopsy was performed, and the results revealed cutaneous T-cell lymphoma (mycosis fungoides). David M. Garzarelli, MD, of Pittsburgh writes that this relatively rare type of non-Hodgkin lymphoma occurs when T lymphocytes become cancerous and invade the skin. In the United States, the incidence of cutaneous T-cell lymphoma is increasing. Some experts think that chronic bacterial skin infections may predispose affected persons to the disease. African American men, usually between 40 and 60 years, are at a slightly increased risk.¹ The 2 major subcategories of cutaneous T-cell lymphoma are mycosis fungoides and Szary syndrome.² Mycosis fungoides is more common, has a slower course, and primarily affects the skin. Szary syndrome is more aggressive and is often associated with redness of the skin (red man syndrome). Typically, cutaneous T-cell lymphoma develops gradually over a prolonged period (several years). The disease process is divided into 3 stages: the erythematous stage, the plaque stage, and the tumor stage.³ In the initial stages, the disease presents as a dry, patchy, erythematous area that is usually pruritic. It is often mistaken for other chronic skin conditions, such as psoriasis and eczema. In the plaque stage, induration, elevation, and central clearing of the lesions may be evident; the differential diagnosis includes psoriasis and tertiary syphilis. The tumor stage carries a poor prognosis, and the tumors often develop ulceration with secondary bacterial infection. Because cutaneous T-cell lymphoma can resemble other skin conditions, a high index of suspicion is required. Do not be hesitant about performing a biopsy and additional biopsies over time. It may take several years to establish a diagnosis. Another helpful diagnostic test is the T-cell receptor gene rearrangement analysis.⁴ After the diagnosis is confirmed, staging procedures are performed. These may include a chest radiograph; CT scan of the abdomen and pelvis; lymph node biopsy, if indicated; and laboratory studies, such as a quantitative Szary cell count, complete blood cell count, and measurement of the lactate dehydrogenase level.⁵ Treatment is based on the results of staging and commonly includes phototherapy, radiation therapy, and chemotherapy. Biologic response modifiers also have been shown to be effective.⁶ This patient was referred to a dermatologist for staging of her lymphoma, and phototherapy was initiated. The rash has been eradicated, and the lymphoma has not progressed. The prognosis for patients with cutaneous T-cell lymphoma limited to the skin is usually good, while those with extracutaneous disease have a poorer prognosis.⁷ Close follow-up of all patients with chronic rashes is important. Monitoring should include repeated biopsies of skin lesions if they progress or change over time.