What are the other Names for this Condition? (Also known as/Synonyms)

• Persistent Melanocytic Naevus
• Pseudomelanoma of Skin
• Recurrent Melanocytic Nevus

What is Persistent Melanocytic Nevus? (Definition/Background Information)

• A nevus (plural nevi) is a mole on the skin that can occur on any part of the body. A common mole is benign tumor of melanocytic (pigment-based) cells that occur on the skin
• Persistent Melanocytic Nevus is recurrence of benign melanocytic nevi at the site of its surgical removal. This takes place due to an incomplete removal of the skin lesion
• The nevus that recurs is usually a compound mole or an intradermal mole. This skin condition is also known as Recurrent Melanocytic Nevus
• The recurrence may take place within some weeks or months. Procedures that may result in Persistent Melanocytic Nevus include shave techniques and laser therapy
• The presence of a prior scar tissue may make the diagnosis challenging to the pathologist, in some cases. Also, in rare instances, they may resemble desmoplastic melanoma. Hence, a careful examination, taking into account the patient’s prior surgery in the area, is often required for an accurate diagnosis
• Treatment, including surgery, may be provided based on the assessment of the healthcare provider, especially if it presents cosmetic issues. The prognosis is generally excellent with adequate treatment

Who gets Persistent Melanocytic Nevus? (Age and Sex Distribution)

• Persistent Melanocytic Nevus is typically observed in individuals who have undergone surgery for removal of a mole
• Both males and females are affected and there is no gender bias observed
• All racial and ethnic groups are at risk

What are the Risk Factors for Persistent Melanocytic Nevus? (Predisposing Factors)

The primary risk factor for Persistent Melanocytic Nevus development is the incomplete removal of melanocytic nevus/mole. This may occur following procedures such as:

• Laser therapy
• Shave removal of the mole
• Excisional surgery of the mole

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Persistent Melanocytic Nevus? (Etiology)

Persistent or Recurrent Melanocytic Nevus develops from a surgical site, from where a nevus/mole was surgically excised either partially or incompletely. The recurrence may take place within a few weeks to months following the surgical procedure.

What are the Signs and Symptoms of Persistent Melanocytic Nevus?

The signs and symptoms of Persistent Melanocytic Nevus that may be observed include:

• Formation of a nevus at a surgical site or from a surgical scar. In a majority of cases, the existing nevus is a compound or intradermal nevus
• The borders of the newly arisen ‘recurrent’ nevus is typically irregular
• A Persistent Melanocytic Nevus may be present as a papule, macule, or plaque
  • Papule: A papule is an area of abnormal skin tissue that is less than 1 centimeter around. Usually a papule has distinct borders, and it can appear in a variety of shapes
  • Macule: A macule indicates the presence of a flat, distinct, discolored area of skin less than 1 cm wide. A macule usually does not involve any change in the thickness or texture of the affected skin
  • Plaque: A plaque indicates a broad, raised area on the skin; it is usually broader than it is high
• The recurrent nevus or mole may be slow-growing and non-uniformly pigmented. A majority of the recurrences take place within a few weeks to months (following the first removal)

How is Persistent Melanocytic Nevus Diagnosed?

A Persistent Melanocytic Nevus is diagnosed through the following tools:

• Complete physical examination with evaluation of medical history: A previous history of surgical excision/removal of a mole, followed by its recurrence at the same site, is essential to establish a diagnosis
• Dermoscopy: It is a diagnostic tool where a dermatologist examines the skin using a special magnified lens
• Wood’s lamp examination: In this procedure, the healthcare provider examines the skin using ultraviolet light. It is performed to examine the change in skin pigmentation
• Skin biopsy: A skin biopsy is performed and sent to a laboratory for a pathological examination. The pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis

In some of the cases, no biopsy is necessary. But it may be performed to rule out other conditions presenting similar signs and symptoms, chiefly a recurrent melanoma.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Persistent Melanocytic Nevus?

There are frequently no complications that arise from a Persistent Melanocytic Nevus.

• Nevertheless, in some individuals, it may give rise to cosmetic concerns
• Scratching or itching of the moles may lead to bleeding and ulceration. This can cause secondary bacterial or fungal infections to develop
• Emotional stress due to fear of skin cancer such as a melanoma
• Trauma due to surgery at the same site more than once

How is Persistent Melanocytic Nevus Treated?

The treatment measures for Persistent Melanocytic Nevus include:

• In some cases, the healthcare provider may choose to regularly observe the recurred mole, to check for any atypical features (a “wait and watch” approach may be followed)
• Surgical excision and removal of the mole, if necessary, for cosmetic reasons
• Follow-up care with regular screening and check-ups are important and encouraged

How can Persistent Melanocytic Nevus be Prevented?

Persistent Melanocytic Nevus may be prevented through complete surgical removal of the melanocytic nevus.

What is the Prognosis of Persistent Melanocytic Nevus? (Outcomes/Resolutions)

The prognosis of Persistent/Recurrent Melanocytic Nevus is generally excellent on adequate treatment, such as a complete excision and removal of the recurrent lesion.

Additional and Relevant Useful Information for Persistent Melanocytic Nevus:

• Do not pick or scratch the moles

Cleaning the skin too hard with strong chemicals or soaps may aggravate the skin condition. Care must be taken avoid strong soaps and chemicals that could potentially worsen the condition