Leukemia cutis is a rare form of leukemia that causes skin lesions. The appearance of the lesions varies significantly from person to person. Lesions may appear as small or large lumps, thickened, flat patches, or discolored dry skin.

Because leukemia cutis can vary so much, people may mistake the lesions for other skin conditions, such as psoriasis or eczema.

Lesions can appear before or after a leukemia diagnosis, but they usually develop afterward. Often, these lesions indicate that the leukemia is at an advanced stage. Depending on where the lesions appear and how they look, they can be a difficult symptom to manage, affecting a person’s physical and mental health.

This article looks at leukemia cutis, including its symptoms, diagnosis, treatment, and outlook.

Leukemia is a type of cancer that affects blood-forming cells. These are cells that will go on to become a type of blood cell, such as a red blood cell, white blood cell, or platelet. If these cells become cancerous, they start growing out of control and can spread around the body via the bloodstream.

Leukemia cutis occurs when leukemia cells affect the skin, forming clusters within the layers of tissue. When this happens, visible patches or lesions appear. It is a rare symptom of leukemia, occurring in only 3% of people with the disease.

Leukemia cutis may develop before or after someone receives a leukemia diagnosis. However, in 55–77% of cases, leukemia cutis develops after a leukemia diagnosis.

Doctors refer to leukemia cutis that occurs before a diagnosis as “aleukemic cutis.” People with aleukemic cutis go on to develop acute myeloid leukemia (AML).

Leukemia cutis lesions can vary in appearance. They may be:

  • small lumps (papules)
  • large lumps (nodules)
  • thickened, flat patches (plaques)

Most of the time, lesions do not cause itching or soreness. They may be the same color as a person’s skin or may appear gray, red, brown, yellow, or blue. They commonly appear on the head, neck, or trunk or at the sites of injuries.

Rarely, leukemia cutis lesions may present as:

  • blisters
  • ulcers
  • dark, ring-shaped rashes
  • eczema-like areas of thickened, inflamed skin
  • red or purple patches that result from bleeding under the skin

Some people may have additional leukemia symptoms alongside leukemia cutis. These can include:

  • fever
  • night sweats
  • tiredness
  • easy bruising or bleeding
  • loss of appetite
  • weight loss

However, some forms of leukemia do not cause symptoms at first. Whether a person experiences other symptoms can depend on the type of leukemia they have and the speed of its growth.

Learn more about the types of leukemia.

Various factors can increase a person’s chance of developing leukemia cutis. One of the most important is the type of leukemia a person has.

While any form of leukemia can cause skin symptoms, the subtypes most associated with it are:

  • myeloid leukemias, such as AML
  • B-cell leukemia/lymphomas, such as chronic lymphocytic leukemia (CLL)
  • T-cell leukemia/lymphomas

Of these, the type most likely to cause leukemia cutis is adult T-cell leukemia/lymphoma (ATLL). However, this type of leukemia is rare.

Leukemia cutis appears in 10–15% of AML cases. Specific AML subtypes, such as acute myelomonocytic leukemia, have a much greater risk of leukemia cutis.

Children with congenital leukemia are also prone to developing leukemia cutis, with up to 30% experiencing this symptom. However, congenital leukemia is extremely rare, accounting for only 1% of childhood leukemias.

Certain environmental and genetic factors also increase the risk. People are more likely to develop leukemia, including leukemia cutis, if they have exposure to:

  • benzene
  • ionizing radiation
  • alkylating agents
  • certain viruses

Most people with leukemia cutis will already have a diagnosis of systemic leukemia, making the cause of the lesions clear. However, in some cases, people develop these lesions before they receive a leukemia diagnosis. This makes diagnosis more challenging, as the lesions may look similar to other conditions.

A doctor who thinks a person has leukemia cutis will look at the lesions and ask about the person’s symptoms. They will also perform diagnostic tests, which will typically include:

  • a complete blood count
  • a blood smear, in which a medical professional examines a blood sample under a microscope
  • a bone marrow biopsy, which involves taking a small sample of bone marrow for examination
  • a skin biopsy, which involves taking a tissue sample from one of the lesions

Doctors may also order tests to determine how well the kidneys and liver are functioning and how well the blood is clotting, to obtain a complete metabolic profile, and to check for other biomarkers for cancer.

If a person has a fever, the doctor should test for infections immediately, because even minor infections in people with leukemia can be serious.

When considering treatment for leukemia cutis, a doctor will make recommendations based on the type of leukemia that is causing the skin lesions.

“Watchful waiting” is an approach doctors use for slow-progressing forms of leukemia, including CLL and chronic myeloid leukemia. As the name suggests, this involves frequently testing and monitoring a person’s leukemia but holding off on using any systemic treatments until the cancer has progressed.

However, if a person has open wounds from leukemia cutis, doctors may prescribe antimicrobial medications to prevent infections.

Other treatments can alleviate the symptoms of leukemia cutis by moisturizing the skin, numbing pain, and speeding up healing. For burns and sores related to leukemia cutis, a person may use steroid creams, topical lidocaine, or menthol lotions.

Doctors may recommend chemotherapy for acute or rapidly progressing forms of leukemia, such as AML. If effective, this systemic treatment will improve underlying leukemia and its impact on the skin.

However, chemotherapy kills some healthy cells in addition to cancerous ones. If an individual undergoes chemotherapy, doctors will monitor them for possible infections.

Other possible treatment options for symptomatic leukemia and associated skin lesions include:

  • radiation therapy
  • stem cell transplant, alone or in combination with chemotherapy
  • bone marrow transplant
  • targeted therapy drugs
  • immunotherapy
  • rituximab, a type of targeted therapy that doctors may recommend in combination with immunotherapy or chemotherapy

While leukemia cutis is rare and is not fatal on its own, it often indicates an advanced stage of leukemia. This may mean a shorter survival time.

The presence of leukemia cutis means that a person may need intensive treatment as soon as possible. It may also indicate a complication of leukemia known as extramedullary disease (EMD). EMD occurs when leukemia involves several organ systems, such as the skin, lymphatic system, nervous system, and liver.

Leukemia cutis can be difficult to cope with mentally, as it can change a person’s appearance and make them feel self-conscious. On top of the demands of cancer treatment, this may affect someone’s mental health.

If someone is having trouble managing leukemia cutis, they can seek support from cancer support groups or therapists with experience in treating people with chronic diseases.

Leukemia cutis occurs in people with leukemia and is the result of cancerous cells infiltrating the skin. This causes the formation of bumps, nodules, and lesions, which can vary in appearance.

Most people with leukemia cutis will already have a leukemia diagnosis, but the lesions sometimes appear before diagnosis.

Doctors treat leukemia cutis by addressing the systemic leukemia that is causing it. Depending on the type and stage of leukemia, treatment may involve a stem cell or bone marrow transplant, targeted therapies, or chemotherapy.