Recognizing clinical signs key to diagnosing CTCL

April 1, 2006

The International Society for Cutaneous Lymphoma has several workshops on criteria for early diagnosis of mycosis fungoides. The criteria used at the Yale Cancer Center were developed from one of those workshops. The algorithm for the diagnosis of early mycosis fungoides uses the basic equation of dermatology.

In the case of the most common CTCL, mycosis fungoides, "If you can diagnose this disease early in its course and get it into remission, the long-term outcome for these patients is excellent," according to Peter W. Heald, M.D., professor of dermatology at the Yale University School of Medicine in New Haven, Conn. The important thing is "To make a diagnosis at a stage at which the condition does not affect long-term survival as long as adequate therapy is provided."

Scoring system

Dr. Heald tells Dermatology Times, "We grade the lesion morphology, the distribution of lesions on the patient and the biopsy. Each of these criteria is graded on a scale that weighs how they contribute to the strength of a diagnosis." This simple grading system divides patients into having classic, consistent or atypical characteristics for each parameter.

"It is important for dermatologists to recognize what makes up a classical morphology, classical distribution and classical biopsy, and likewise for characteristics considered to be consistent or atypical," Dr. Heald says.

Classic characteristics

A classic lesion might present as a 5 cm or greater patch with atrophy, wrinkling of skin and fine scales (a maculo-squamous lesion). Often, blood vessels can be observed in the lesion due to thinning of the skin. This patient would be considered to have a classic lesion. In terms of distribution, a classic location for lesions would be the typical bathing trunk areas of the buttocks, groin and breasts.

A morphologically classic lesion in a classic location would be fairly sufficient for making the diagnosis provided the biopsy does not show another process. However, Dr. Heald emphasizes the importance of the histology in making the diagnosis of mycosis fungoides.

"The importance of using this three-part scoring system," he explains, "is that if you have a patient with lesions that look like mycosis fungoides and are in a common location and the biopsy is interpreted as being consistent with that disease, then there are enough criteria to make the diagnosis."

Utility of scoring system

This scoring system can be useful in making a difficult diagnosis. Dr. Heald notes that two classic features can often signal a diagnosis of mycosis fungoides. For example, lesions demonstrating classical distribution and morphology may carry a biopsy that is somewhat in between.

"What vexes dermatologists is that if they receive biopsy results that indicate possible lymphoma, they are not sure what else to do. With these clinical criteria, they can pretty much rule out and rule in conditions that come close to mimicking mycosis fungoides."

Dr. Heald and his colleagues undertook a small study evaluating the utility of the 3 x 3 scoring system. They evaluated 42 patients who presented with mycosis fungoides after the scoring criteria were developed, and they looked for correlations between the parameters. For example, they evaluated whether patients with classic lesions by morphology all had classic biopsies. Interestingly, the categorizations of the different parameters did not correlate.

Dr. Heald explains, "It was not as if patients with the most typical lesions by physical exam had the most typical biopsies."

Secondly, investigators found that over time, the duration of lesions did not correlate with the strength of diagnosis by biopsy.

"This has always been a notion, to wait for the disease to become positive," Dr. Heald says. "However, if the lesions are left alone, the histology may not change but the disease may progress."