A Guide to Desmoplastic Melanoma

Medically Reviewed By Raechele Cochran Gathers, MD
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Desmoplastic melanoma (DM) is a form of skin cancer. It is a rare condition where melanocytes, the cells that create melanin, begin to grow out of control. Fibrous tissue surrounds the malignant cells and may affect the nerves. Desmoplastic melanoma (DM) sometimes starts growing underneath another type of skin cancer called lentigo maligna, which affects only the first layer of skin.

This article discusses DM and its types, causes, symptoms, and treatments. It also discusses the outlook for people with the condition, potential complications, and prevention methods.

Types

An older man looking at his face in the mirror
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There are two forms of DM, pure desmoplastic melanoma (PDM) and mixed desmoplastic melanoma (MDM).

  1. In PDM, at least 90% of the melanoma is desmoplasia, or fibrous or connective tissue growth.
  2. In MDM, melanoma contains less than 90% of desmoplasia and a high cellular density.

Causes

Though experts are unsure what causes skin cells to become malignant, genetic mutations may be a contributing factor.

UV radiation from the sun or tanning beds may be one of the causes of these mutations. According to experts, more than half of DM cases involve the sun-exposed areas of the head and neck.

Heredity may also play a role in the development of DM. For example, if someone in your immediate family has had skin cancer, you may be at a higher risk of developing it.

Stages

Staging is the process of analyzing cancer spread. Doctors use staging to determine the severity of cancer and appropriate treatments.

For skin cancer, doctors look at how many layers of skin are affected, if there is any ulceration, and if it has spread to nearby lymph nodes or other areas of the body.

The stages for DM are the same as the stages for all melanomas. Below are the general stages of melanoma.

  • In Stage 0, the cancer is only in the first layer of the skin.
  • In Stage 1, the tumor is less than 2 millimeters (mm) thick and may or may not have ulceration.
  • In Stage 2, the tumor may be more than 2 mm thick or more than 1 mm thick with ulceration.
  • In Stage 3, the cancer has spread away from the primary tumor and may be affecting nearby lymph nodes.
  • In Stage 4, the cancer has spread into distant parts of the body.

Learn more about the stages of melanoma.

Symptoms

DM typically starts as an area of thickened skin that grows slowly. Some people describe it as scar-like tissue. Sometimes it’s the same color as your skin. In other cases, it may be:

  • pink
  • brown 
  • gray
  • blue
  • black

As time progresses, the area becomes more distinct. The tumor may be flat against the skin or raised. Usually, the borders are irregular, but they may also be regular.

A melanoma that has spread farther into the skin may be thicker, have more colors, and cause ulcerations or bleeding. Some people may also experience stinging or itching in the area.

Diagnosis

If your doctor suspects you have melanoma, they will examine the area, often with dermoscopy. They will take a biopsy of the tissue.

Depending on the findings from the biopsy, they may order a sentinel lymph node biopsy. This checks the surrounding lymph nodes for cancer cells. Imaging studies and blood tests may also be necessary.

Treatments

The first treatment for DM is surgical excision. A surgeon will remove the tumor and, more than likely, some of the surrounding skin or margins. They will probably remove the sentinel lymph nodes as well.

Learn more about surgical procedures for melanoma.

Your doctor may also recommend radiation therapy for DM, especially in specific circumstances:

  • if the subtype is PDM
  • if the tumor is thicker than 4 mm
  • cancer cells are in the margins of the area removed during surgery
  • the tumor has invaded the nerves

Learn more about radiation therapy.

Immunotherapy may be an option as well. Immunotherapy drugs can help your body’s immune system recognize and target abnormal cell growth.

Learn more about immunotherapy.

Outlook

There are conflicting reports about prognostic indicators and outcomes for people with desmoplastic melanoma. One factor to keep in mind is that the thicker your tumor at the time of surgical removal, the more likely it is to spread.

Cancer cells in close lymph nodes indicate an increased risk of cancer spreading to distant areas. If you have MDM, you have a higher risk of lymph node involvement.

Complications

The main complications of DM are its potential to spread into the body or recur after treatment. The most common site of recurrence after treatment is in the same area where it developed before.

As with all melanomas, surgery for DM may cause extensive scarring, depending on how much tissue needs to be removed.

Risk factors

Specific risk factors can increase your chances of developing DM, such as:

  • Age: The older you are, the higher your chances of developing DM. 
  • Sex assigned at birth: People assigned male are more likely to develop DM than those assigned female at birth.
  • Your skin color: People with light skin are much more prone to developing DM.
  • Sun damage: If you are frequently sunburned, you have a higher chance of developing DM.
  • History of melanoma: If you have had melanoma, you have a greater chance of developing DM.

Prevention

You cannot control many of the factors that contribute to skin cancer. Your age, sex assigned at birth, skin color, and family history are out of your control.

However, you can protect your skin from sun damage. The American Academy of Dermatology Association recommends:

  • staying out of the sun when it’s strongest, generally from 10 a.m. to 2 p.m.
  • wearing sunscreen with a sun protection factor (SPF) of at least 30
  • reapplying sunscreen every two hours
  • avoiding sunbathing or using tanning booths
  • wearing more clothes to cover more skin

Summary

DM is a skin cancer that frequently begins on your head or neck. Sometimes it will start in the same area as another type of melanoma. Most doctors believe skin cancer is caused partly by changes in your DNA because of sun exposure. 

Protecting yourself from excessive sun exposure may decrease your chances of developing DM. Talk with your doctor about ways you can protect yourself.

In addition, talk with your doctor if you notice an area of skin that seems to be growing, thickening, or changing color. These may be signs of skin cancer. The earlier skin cancer is caught, the easier it is to treat.

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Medical Reviewer: Raechele Cochran Gathers, MD
Last Review Date: 2022 Nov 29
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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  3. How to prevent skin cancer. (n.d.). https://www.aad.org/public/diseases/skin-cancer/prevent/how
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