Penile mucosal melanoma

Penile mucosal melanoma can be found in and around the penis (glans, foreskin, shaft, meatus or scrotum). It is a very rare type of melanoma, accounting for only 0.1% of all cases. It may show as a dark pigmented area with irregular borders.

Types of penile mucosal melanoma

Penile mucosal melanoma can be found anywhere in this part of the body, but is found in the rounded tip of the penis (glans) in over half of cases, followed by the foreskin. Around 1 in 10   melanomas are located in the shaft, and it can sometimes be found in the space or hole at the tip of the penis through which you pass water (urethral meatus). The scrotum is another area where a melanoma can form. 

Penile mucosal melanoma starts in the pigment-producing cells (melanocytes) like other melanomas. The melanoma may be darker than the surrounding areas, appearing blue-black or brown in colour, with an irregular border. In some cases the melanoma does not have more pigment or is colourless (amenalotic). 

Melanoma affecting the scrotum or skin on the penile shaft is similar to skin melanoma (superficial spreading type of melanoma).

What are the causes?

The causes of penile mucosal melanoma remain largely unknown and may be a combination of age, genetics and environmental factors. Penile melanoma can be found in men of any age, but it  is most commonly found in individuals over 60.

Symptoms

The most common symptoms of penile melanoma is a lesion, mass or growth in the area. This may be blue-black, or brown in colour with an irregular border.

Other possible symptoms include: 

  • A lump, growth or swelling in the groin
  • Itching in the penis
  • Pain in the penis
  • Difficulty urinating (passing water)
  • Abnormal discharge from the penis
  •  

The symptoms are often similar to other symptoms of types of cancer in the penis. These symptoms can also have a non-cancer related cause. It is therefore important to arrange an early appointment with your GP, so they can take the most appropriate action quickly.  

If your GP cannot find another cause for these symptoms, you should be referred quickly (normally within about two weeks) to a specialist clinic in male genital cancer for tests. This may involve an appointment with a urologist or urogenital cancer consultant, melanoma specialists and nurse specialists.
 

Penile mucosal melanoma: Diagnosis and staging

It is important you see your GP if you have symptoms or any unexplained symptoms that are worrying you. If your GP has any concerns or if they are not sure what the problem is, they will refer you to a hospital specialist who will examine you and will arrange for you to have a biopsy. This is a small sample of the tissue that will be removed under local anaesthetic to look for cancer cells. It is then analysed by a pathologist (a specialised doctor who diagnoses diseases from tissue and cells in the body) to decide whether it is a melanoma or not. 

It typically takes a few weeks to receive the results of your biopsy and this can be a very anxious time. You may have other tests to help diagnose penile mucosal melanoma and these tests can also be used to check whether your melanoma has spread to other parts of the body.
 

Determining your stage for penile mucosal melanoma 

After a diagnosis of penile mucosal melanoma, your medical team will work out the ‘stage’. The stage is a way of describing the key features of your melanoma and is helpful in guiding the best treatment and follow-up for you. Your stage provides an indication of how advanced your melanoma is. Generally, the higher the stage, the more advanced it is. Staging for penile mucosal melanoma is not the same as the standard type for melanoma (American Joint Committee on Cancer – AJCC TNM system). It is more common to use the staging below.

Stage 1= the melanoma is ‘localised’ which means it is only in the penile area and it has not spread anywhere else

Stage 2= the melanoma has spread to nearby lymph nodes

Stage 3 = the melanoma has spread to other parts of the body (metastasised).

Some mucosal melanomas in this area are found to be similar to skin cancer and are staged in the same way. This is known as the TNM system. This is based on how big the tumour is (T), whether it has spread to nearby lymph nodes (N), and if there is spread to other organs (M – metastasis).

> You can find more detail about TNM staging for skin cancer here 

Penile mucosal melanoma: Treatment

Surgery

The main treatment for penile mucosal melanoma is surgery. This should be done by a surgeon who is very experienced in male urogenital cancer surgery, in a specialised centre, with support from an experienced cancer team.

There are a number of different approaches to surgery for penile mucosal melanoma, depending on its location and how advanced it is.
In planning the operation, the medical team will consider the stage of your penile mucosal melanoma, your general health and how the surgery may affect your quality of life.

Since this is an intimate part of your body, you may want further support or counselling to help with the emotional aspects and consequences of surgery. Your medical team should be able to provide you with details.

Other possible treatments

If the penile mucosal melanoma has spread to other parts of your body you may be offered other treamtents or the option of taking part in a clinical trial. For more information on clinical trials, please visit the Melanoma TrialFinder.

If you have any questions about your diagnosis or treatment, our specialised Melanoma Helpline nurses are here to support you on 0808 801 0777  

References

Carvajal RD, Spencer SA, Lydiatt W. Mucosal Melanoma: A Clinically and Biologically Unique Disease Entity. J Natl Compr Canc Netw (2012) 10(3):345–56. doi: 10.6004/jnccn.2012.0034

Omer Onur Cakir Edoardo Pozzi et al., Clinical features, molecular characteristics and surgical

management of primary penile mucosal melanoma (2021) Melanoma Res 32: 27–34 DOI: 10.1097/CMR.0000000000000788

Rambhia PH, Scott JF, Vyas R, et al. Genitourinary Melanoma. Chapter 5. (2018) Available from: https://www.ncbi.nlm.nih.gov/books/NBK506990/ doi: 10.15586/codon.noncutaneousmelanoma.2018.ch5