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CTCL Diagnosis: What to Expect

by Ravi Ubriani, Cutaneous Oncology Fellow, University of Pennsylvania

Cutaneous T-cell lymphoma (CTCL) is a complex disorder which often takes a significant amount of time to diagnose. Various studies indicate that the average time from first appearance of symptoms to confirmed diagnosis of the disease range from two to seven years. This delay can lead to frustration for both a patient suspected of having CTCL and his or her physician.

There are two main reasons why the diagnosis of CTCL can take time to confirm. The first is that the disease can take many different forms in the skin. Lesions can be flat spots, raised areas, or large lumps. The disease can appear differently in people with different levels of pigmentation. CTCL is often initially misdiagnosed as a much less rare condition such as eczema, psoriasis, or an allergic reaction. It is only after patients do not respond to appropriate treatments that alternative diagnoses are considered.

Even once CTCL is suspected by a physician, the diagnosis can be difficult to make definitively. There is no single test that will be positive for CTCL every time. The most useful test that can be performed is a skin biopsy, in which a small piece of skin is examined under a microscope by a pathologist. This trained specialist can look for features consistent with CTCL. However, lesions that appear very similar on the skin can appear very different microscopically. Many patients require multiple biopsies at three month intervals before a diagnosis is made. Each biopsy provides a limited view of the processes that are occurring in the skin.

The need for multiple sequential biopsies can be very exasperating and difficult to understand for patients. Some pathologists have compared making the diagnosis from a single biopsy to glancing at a party through a keyhole. While one glance might give you some sense of what kind of party it was and who was in attendance, the more times you could look, the more accurate your estimate would become. In the same way, the more times a pathologist can microscopically examine the skin, the higher the chance of making the diagnosis of CTCL.

Besides the skin biopsy, there are other tests that your physician can perform. A type of DNA test can be performed to look for a population of immune cells dividing too often in the skin or blood. This test is called a T-cell gene rearrangement study. Another test, called flow cytometry, looks for patterns in immune cells typical of CTCL. A Sézary prep examines the white blood cells to look directly for malignant cells. Testing for a virus called HTLV is sometimes performed based on a patient’s history. A lymph node biopsy can sometimes aid in the diagnosis.

The diagnosis and care of CTCL often involves internists, dermatologists, and oncologists. For this reason, it is often necessary to see a clinic specialized in the care of CTCL. At such a center, there are often pathologists specially trained to examine skin. Certain tests may also only be available at such specialized clinics. Today there are many effective treatments for CTCL, and it is important to stay positive and remain patient, even when multiple and repeated tests are required.

Glossary of terms:

skin biopsy: a procedure in which a small piece of skin (about the size of a pencil eraser) is removed with a circular blade and examined under a microscope. This is done in the office by a dermatologist. It takes about five minutes and usually requires one to two stitches.

T-cell gene rearrangement study: a DNA-based test that looks for the presence of a larger than usual population of one type of immune cell. This can be done on either a skin biopsy or a blood sample.

flow cytometry: a blood test that looks for molecules on the surface of white cells that CTCL cells usually express.

Sézary prep: a blood test that directly looks for the CTCL cells

HTLV: a virus endemic to the Middle East and Japan that can cause a variant form of T-cell lymphoma. The blood can be tested for this infection.

lymph node biopsy: a procedure in which a small piece of lymphatic tissue is removed and examined under the microscope. A lymph node is part of the immune system. There are different ways this test can be performed, spanning a range of intensity. Your doctor can discuss the various options with you.