Over the past 4 decades, cutaneous T-cell lymphoma diagnoses have been on the rise, especially among black and other skin of color patients. Unfortunately, this form of skin cancer can be a diagnostic challenge.
Regarding diagnosis, cutaneous T-cell lymphoma (CTCL) is the wild card of dermatology; it is a great mimicker of many skin disorders, and can look like almost anything. However, the most striking feature of the condition – and the key to diagnosis in ethnic skin – is its polymorphous pigmentation that is unique to skin of color.
Photo (c) Elsevier
Look out for the "herald patch" of unilesional mycosis fungoides, which takes the form of a single large, dyspigmented patch
CTCL lesions may be flat or raised, and may mimic other skin disorders associated with pigment change. These can include tinea versicolor, vitiligo, pityriasis rosea, and psoriasis. Lichen planus pigmentosus and progressive macular hypomelanosis are other important CTCL mimickers. Consider all of these conditions in the differential diagnosis.
An excellent resource for photos and descriptions of CTCL, as well as CTCL look-alikes, is an article by Dr. Ginette A. Hinds and Dr. Peter Heald (J. Am. Acad. Dermatol. 2009;60:359-75). The article also highlights the clinical variants within the mycosis fungoides subtype, the most common form of CTCL among blacks.
For example, look out for the "herald patch" of unilesional mycosis fungoides, which takes the form of a single large, dyspigmented patch. According to the authors, this variant has an excellent prognosis, possibly because of an active immune response that limits the initial spread of disease and contributes to preventing relapse.
Photo (c) Elsevier
The most striking feature of cutaneous T-cell lymphoma – and the key to diagnosis in ethnic skin – is its polymorphous pigmentation (shown here) that is unique to skin of color.
Another variant is pigmented purpuric mycosis fungoides, which can often be confused with the benign pigmented purpura syndromes of Schamberg’s disease (progressive pigmented purpuric dermatitis), Gougerot-Blum syndrome (pigmented purpuric lichenoid dermatitis), Majocchi’s disease (purpura annularis telangiectodes), Doucas and Kapetanakis (lymphocytic capillaritis of unknown cause), and lichen aureus. The key to diagnosis in this case is recalling that "the lesions of the benign syndromes rarely assume the morphology and distribution found with mycosis fungoides," Dr. Hinds and Dr. Heald wrote.
Not only is mycosis fungoides difficult to diagnose, but it is especially prevalent among black patients. For instance, a 1988 study looking at Surveillance, Epidemiology, and End Results (SEER) data from 1973 through 1984 found that the incidence among black patients was twice that of white patients: 0.52/100,000 vs. 0.26 (JAMA 1988;260:42-46).
Similarly, in another study of 132 black patients with skin cancer, mycosis fungoides represented 12.1% of all skin neoplasms (Dermatol. Clin. 1988;6:397-405).
Mycosis fungoides is the fourth most common skin cancer among Japanese patients, representing approximately 5% of all skin malignancies in the population.
Dr. Wendy Roberts
The incidence of CTCL and its subtypes is only increasing. A 2007 study that extended the SEER data mentioned above from 1973 to 2002 and included all CTCL cases found an incidence rate of 9.0 for black patients, per 1 million person-years, compared with 6.1 for white patients (Arch. Dermatol. 2007;143:854-9).
As in many skin cancers, early diagnosis can make the difference in successful outcomes. So add CTCL, and especially the mycosis fungoides subtype, to your differential when confronting pigmentation disorders in skin of color patients.
Dr. Roberts is past president of the Women’s Dermatologic Society (WDS) as well as past president of the California Society of Dermatology and Dermatologic Surgery (Calderm). She was a founding director of dermatopathology at the Loma Linda University Medical Center (Calif.). She currently runs a private practice in Rancho Mirage, Calif.
She disclosed financial relationships with Allergan, L’Oréal/La Roche Posay, Skin Medica, and Valeant Pharmaceuticals.