Many practitioners initially suspect a diagnosis of psoriasis, eczema or a drug reaction - three of the more common possibilities that are considered when a physician is actually about to diagnose cutaneous lymphoma.
Washington - Dermatologists are occasionally confronted with a difficult-to-treat rash that is recalcitrant to standard therapies, and these sometimes perplexing cases may be the beginnings of mycosis fungoides, the most common type of cutaneous T-cell lymphoma (CTCL).
According to one expert speaking at the 65th Annual Meeting of the Academy of Dermatology, here, approaching these ambiguous eruptions by systematically defining morphology and location, as well as ruling out the differential gamut, is key to securing a diagnosis of the mycosis fungoides variant of CTCL.
"Cutaneous T-cell lymphoma can sometimes mimic a lot of other skin diseases clinically, and biopsy results oftentimes are noncommittal or indeterminate, leaving dermatologists in a diagnostic limbo," says Peter Heald, M.D., professor of dermatology at Yale University School of Medicine, New Haven, Conn.
"Some of the more common questions and common consultations that are sent my way basically involve patients with a biopsy result that is suggestive or suspicious of cutaneous T-cell lymphoma, but not conclusive," Dr. Heald tells Dermatology Times.
Dr. Heald says that many practitioners initially suspect a diagnosis of psoriasis, eczema or a drug reaction - three of the more common possibilities that are considered when a physician is ready to diagnose cutaneous lymphoma. He says that many different diseases can result in ambiguous language on the biopsy report, with wording such as "suspicious of" or "consistent with" CTCL. But these diseases look slightly different. So, the clinical aspect plays a significant role in feeding the suspicions of the dermatologist in diagnosing CTCL.
"Probably the most common example is a rash that is just not responding to standard therapy as expected. You want to double-check and make sure it is really what you think it is," Dr. Heald says.
Other conditions that could require biopsy and may be mistaken for a skin lymphoma include pityriasis lichenoides and digitate dermatosis. Yet these conditions do not create 5 cm, atrophic, scaling, annular lesions on the buttock - a classic location and classic appearance of cutaneous T-cell lymphoma.
Factors to aid diagnosis
Dr. Heald says the clinician can follow a three-part checklist to help secure a definitive diagnosis of CTCL:
"If a dermatologist is still uncertain about the diagnosis after utilizing the three-point checklist, that might be the time to then consider asking for a consultation, to see if it is an evolving disease or some other rare syndrome," he says.
Dr. Heald says that once a T-cell lymphoma is diagnosed and classified, the clinician must stage the lymphoma and develop a prognosis for the patient.
Knowing what exam to order can prove to be a daunting task, as an arsenal of technologies and diagnostic techniques is available, including PET scans, CT scans, flow cytometry and gene studies.
"For stage Ia disease, which is less than 10 percent of the body surface, no additional staging studies are indicated. There is no need for scans, flow cytometry or bone marrow biopsy. Flow cytometry (specialized blood tests for the disease) studies can be done from stage Ib on up. Also, though a lot of physicians do bone marrow biopsies, I do not think there is ever a need or reason to do this procedure unless you are looking for something else like B-cell CLL," Dr. Heald says.