Written by

Steven Horwitz, MD, Medical Oncologist, Memorial-Sloan Kettering Cancer Center

Reviewed: Medical Advisory Council (August 2019)

Uncommon diseases pose a number of challenges

One of the most difficult things about uncommon diseases for both patients and physicians is reaching a correct diagnosis. 

A definitive diagnosis will help inform treatment decisions and potentially yield better patient-related outcomes over time. One of the key concepts for patients and their caregivers to understand is that a clear diagnosis may take time; in the case of cutaneous lymphoma, a definitive diagnosis sometimes takes years. The best approach for patients is to collaborate and work with their physicians. In milder cases of cutaneous lymphoma, non-cancerous reactive processes such as rashes resulting from medications, external environmental exposures, or inflammatory conditions of the skin (like eczema) can be easily confused with cutaneous lymphoma.

Assessing Skin Lesions

By definition, all cutaneous lymphomas present skin-related symptoms. When a patient presents with skin lesions, their physician will work to differentiate whether the lesions are the result of a reactive process versus a lymphoma of the skin. A reactive process, which can include the body’s response to a bug bite, allergic reaction to medication, or other inflammatory processes of the skin such as eczema or psoriasis, is the gathering of immune system cells, often non-cancerous “T-cell lymphocytes” in the skin to defend against and fight off invading entities; sometimes reactive processes occur for reasons we do not understand.

In contrast, skin lymphomas are cancerous proliferations or an excess of malignant T-cell lymphocytes growing within the skin.

Since reactive processes and other types of inflammation can trigger symptoms similar to those of cutaneous lymphomas, evaluation by a provider with experience in diagnosing skin lymphoma is important if skin lymphoma is suspected. In many cases, test results (such as skin biopsy) may not initially be conclusive, which means they cannot clearly differentiate between a skin lymphoma versus reactive process.

When a diagnosis is not definitive, the patient should discuss options with their physician.

In some circumstances, treatment can begin even without a definitive diagnosis. For example, some patients may wish or receive the recommendation to seek relief from symptoms by starting a treatment such as a topical steroid cream or ointment, or even ultraviolet light therapy. Other patients may prefer or obtain a recommendation to have the physician take additional biopsies of the skin lesion to try to yield more conclusive results. It’s important to understand that in order to get the most effective biopsy, patients should generally be off treatment regimens. While treatments may provide temporary symptom relief, they can also mask potential signs of skin lymphoma and thus delay a definitive diagnosis.

What role does pathology play in my diagnosis?
Dr. Robson provides an overview of the important part pathology plays in diagnosing cutaneous lymphoma and helps answer the often asked question "why did it take so long to get diagnosed?"


Alistair Robson, BSc (Hons), MBChB, FRCPath and DipDermRCPath, Consultant Dermatopathologist, Lisbon Institute of Oncology

The Role of Consistent Biopsies

Skin biopsies over time are often needed to obtain a proper diagnosis. A skin biopsy is a simple outpatient procedure that involves removing a small sample of tissue from the skin for examination. When a biopsy is performed, local anesthetic is given prior to the procedure, and a small core of skin is removed. Stitches may or may not be used. 

Whenever a biopsy is taken, a patient’s doctor, in conjunction with a pathologist (a doctor who studies tissues and cells to identify diseases), will work together to try to obtain the most accurate diagnosis. The pathologist will analyze slices of the biopsy in a holistic way, and look specifically for the presence of an excess number of T-lymphocyte cells that are arranged in certain patterns that can be clues to the pathologist that a patient has a skin lymphoma.

A definitive diagnosis cannot be obtained without a biopsy, and multiple biopsies are often necessary to confirm the diagnosis of cutaneous lymphoma.

Is very important to confirm any diagnosis of cutaneous lymphoma by a specialized type of pathologist - dermatopathologist or a hematopathologist - who has expertise in diagnosing cutaneous lymphomas.

Why are so many skin biopsies required?


Stuart Lessin, MD, Medical Director, KGL Skin Study Center, Broomall, PA

Pierluigi Porcu, MD, Director, Hematologic Malignancies and Hematopoietic Stem Cell Transplantation Division, Sidney Kimmel Cancer Center, Thomas Jefferson University Hospital (At time of publication: Associate Professor of Internal Medicine, Division of Hematology-Oncology, Ohio State University Comprehensive Cancer Center)  

Larisa Geskin, MD, Director, Cutaneous Oncology, Columbia University Medical Center (At time of publication: Associate Professor of Dermatology, University of Pittsburgh)

Finding a Balance

Cutaneous lymphoma is sometimes a progressive and often an incurable disease. In many cases, the disease may be mild and, even without strong treatment, may not progress over time. A clear diagnosis may take time, so patients and their caregivers will require patience and persistence. Accuracy in determining whether a patient has cutaneous lymphoma, and which subset, is paramount in determining the best course of care and treatment. A premature or inaccurate diagnosis could expose the patient to insufficient or unnecessary medication regimens.

If a patient is ever dissatisfied with their diagnosis, they should seek a second opinion, conduct research and visit a cancer center that sees a high volume of cutaneous lymphoma patients. With or without a clear diagnosis, patients should remain under the care of an experienced physician they trust to foster understanding of their disease, diminish frustrations and ensure the road to diagnosis is as manageable as possible.

When is getting a second opinion a good decision? Our panel of experts offer their recommendations on when you should seek out another professional opinion.


Stuart Lessin, MD, Medical Directory, KGL Skin Study Center

Marianne Tawa, RN, MSN, ANP, Nurse Practitioner, Dermatology and Cutaneous Oncology, Dana Farber Cancer Institute

Larisa Geskin, MD, Director, Cutaneous Oncology, Columbia University Medical Center (At time of publication: Associate Professor of Dermatology, University of Pittsburgh)

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