Mycosis fungoides

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at January 11, 2017
StartMycosis fungoides

Mycosis fungoides is the most common type of cutaneous T-cell lymphoma which falls under the category of non-Hodgkin's lymphoma (NHL). Non-Hodgkin's lymphoma involve the malignancy of T-cells and more commonly, B-cells, both of which are types of lymphocytes. Mycosis fungoides is closely associated with Sézary syndrome and primarily affects the skin.

Contents

Definition & Facts

T-cells are a type of lymphocyte which is a subcategory of white blood cells. T-cells, along with B-cells, produce antibodies that fight infection. In mycosis fungoides, the T-cells become malignant, and the cancer can metastasize or spread through tissue, the lymph system, or the blood. Mycosis fungoides is a slow-growing cancer.

This type of cancer affects the skin, manifesting as skin rashes and skin lesions. Mycosis fungoides is more common among males than females, and it occurs in approximately 1 out of 100,000 to 350,000 people. It is unknown what causes mycosis fungoides though genetic factors and environmental factors likely play a role.

Symptoms & Complaints

Mycosis fungoides causes red rashes on the skin. In the disease's early stages, the rash may be scaly but does not otherwise cause symptoms and persists for years. Patches may eventually form which resemble eczema.

These patches can develop into plaques, which are lesions that are hard. Papules can also develop which are small, inflamed pimples. Eventually, tumors can form on the skin. Ulcers and infection may ensue. Skin infections with bacteria such as Pseudomonas aeruginosa and Staphylococcus aureus pose a threat to survival as sepsis can result. The lymph nodes may eventually swell.

Causes

It is unknown what causes mycosis fungoides. There may be chromosomal abnormalities associated with this condition. The human leukocyte antigen (HLA) system or complex may be associated with mycosis fungoides.

Diagnosis & Tests

Any diagnosis will begin with a thorough medical history and family history as well as a physical examination. Any medications the patient is taking or has taken will be noted.

The patient's skin and blood will be examined thoroughly as part of diagnosing this condition. The skin will be examined for the hallmark rashes. Whether they are scaly rashes, papules, thin eczema-like rashes, or tumorous lesions will be noted. A biopsy of the skin may be performed to assess whether or not the lesions are cancerous.

A complete blood count may be performed to assess the patient's quantity and characteristics of red blood cells, white blood cells, hemoglobin (a component of red blood cells that carry oxygen), hematocrit (how much of the fluid part of the blood consists of red blood cells), and platelets (these are components in the blood that assist with clotting). A peripheral blood smear can help show whether or not the blood cells appear normal. It will examine red blood cells, white blood cells, and platelets.

Flow cytometry is another laboratory analysis that examines blood cells. It involves the use of a dye that reacts to light. In addition to measuring the number and size of the cells as well as the amount of DNA in them, this exam can assess whether there are tumor markers on the cell's surface. Tumor markers are usually proteins produced by cancer or other parts of the body.

There are four stages of this disease that describe how far the cancer has spread. imaging studies can assist in diagnosing the stage of the cancer. These include X-rays, computed tomography (CT) scans, and magnetic resonance imaging (MRI) scans.

A lymph node biopsy will also be taken to assess if the cancer has spread. If it has spread to the lymph nodes, the cancer may be described as Stage IV. A needle biopsy of the bone marrow may be necessary to detect signs of cancer.

Treatment & Therapy

Mycosis fungoides can be treated with photodynamic therapy. In this type of therapy, a drug is administered that accumulates in cancer cells and responds to certain types of light. A laser is then applied to the skin and activates the drug. PUVA therapy (psoralen and ultraviolet A therapy) is a type of photodynamic therapy. Psoralen is the drug that is used in this treatment.

Radiation therapy is another treatment option for mycosis fungoides. Radiation may be external beam therapy (external radiation therapy) in which radiation is delivered from outside the body. Radiation therapy can also take the form of internal radiation therapy (or brachytherapy). This involves radiation being sealed and implanted either in or near the tumor site. The benefit to internal radiation therapy is that it enables higher doses of radiation to be delivered due to the minimized exposure of healthy tissues to the radiation.

Chemotherapy may also be an option. Chemotherapy can be topical, regional, or systemic. Gemcitabine, methotrexatepegylated liposomal doxorubicin, and pentostatin are examples of chemotherapy drugs that may be used to treat mycosis fungoides.

Biologic therapy, which is also called immunotherapy, is used to treat mycosis fungoides. Biologic therapy uses living substances to stimulate the body's immune system to fight cancer. Examples could include vaccines, bacteria, and antibodies. Interferon is a type of cytokine that is used in biologic therapy. Cytokines are produced by white blood cells and help improve the immune response, slowing tumor growth. Another type of cytokine used in biologic therapy are interleukins.

Skin lesions may be surgically excised as well. Stem cell transplants may also occur. These include bone marrow transplants and cord blood transplantation. Extracorporeal photopheresis is a procedure in which the patient's blood is drawn and their white blood cells are separated then treated with a substance that makes them sensitive to ultraviolet light. These treated white blood cells are then exposed to ultraviolet light which kills cancerous cells. The blood is then returned to the patient.

Patients are also encouraged to participate in clinical trials.

Prevention & Prophylaxis

Mycosis fungoides is not preventable because its causes are so poorly understood.