What are the other Names for this Condition? (Also known as/Synonyms)
- Acral Naevus
- AN (Acral Nevus)
- Nevi on Volar Skin
What is Acral Nevus? (Definition/Background Information)
- A nevus (plural nevi) is a mole on the skin that can occur on any part of the body
- An Acral Nevus (AN) is a benign condition that occurs as a pigmented skin lesion on the palms or soles. The lesion is usually a poorly-defined flat mole, less than 1 cm in size
- A majority of them arise during childhood and young adulthood. Acral Nevus is observed to occur spontaneously and the cause is largely unknown
- There are also no identified risk factors for the development of the tumor presently, though some scientists believe that it may develop from chronic injury to the skin or from unstable moles
- Acral Nevi do not present any significant complications but may rarely cause cosmetic concerns in some individuals. Unlike a common mole that may disappear with time, Acral Nevus is not known to disappear with time
- Treatment is generally not required for an Acral Nevus unless it presents cosmetic issues. The prognosis is generally excellent, since these skin lesions are benign
The following two conditions are described as the histological subtypes of Acral Nevus:
- Atypical or Acral Lentiginous Nevus
- Melanocytic Acral Nevus with Intraepidermal Ascent of Cells (MANIAC)
Who gets Acral Nevus? (Age and Sex Distribution)
- Acral Nevus is a benign skin tumor that can occur at any age, but is generally noticed in individuals between 10 and 30 years old
- Both children and adults may be observed with this skin tumor
- Both males and females are affected and there is no gender bias observed
- All racial and ethnic groups are at risk. The respective incidence of Acral Nevus among fair-skinned and dark-skinned individuals may vary
What are the Risk Factors for Acral Nevus? (Predisposing Factors)
Currently, there are no identified risk factors for Acral Nevus formation. However, the following may be noted:
- Some studies indicate that repeated injury to the acral region may contribute towards the risk
- The presence of unstable moles developing from preexisting moles
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 Acral Nevus? (Etiology)
The cause of Acral Nevus formation is currently unknown. Some research scientists believe that the following factors may contribute towards its formation:
- Chronic trauma to the region
- Moles that have become ‘unstable’
What are the Signs and Symptoms of Acral Nevus?
The signs and symptoms of Acral Nevus may include the following:
- The presence of a benign, pigmented skin lesion; the color of the lesion is usually light or dark brown
- The pigmented areas may be more prominent on the ridges of the skin than on the grooves of the skin (on the palms and soles)
- The pigmented area is poorly-circumscribed and irregularly-shaped (which can raise the suspicion of a melanoma)
- The lesion is typically not more than 8 mm in size
- Acral Nevus occurs on the hands and feet (acral sites); chiefly on the palms and soles
- These moles are more commonly seen on the palms of the hands, than on the soles of the feet
- The moles may be present anywhere on the surface of the hands and feet (both on pressure-bearing or non-pressure-bearing areas)
How is Acral Nevus Diagnosed?
An Acral Nevus is diagnosed through the following tools:
- Complete physical examination with evaluation of medical history
- 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
- Dermoscopic pigmentation pattern is helpful in distinguishing an acral lentiginous melanoma and a benign Acral Nevus. In a benign Acral Nevus, the pigmentation is along the furrows of the skin markings. In early acral melanoma, the pigmentation is present on the ridges of the skin surface markings. It is important to note that such a dermoscopic examination is mainly performed by a trained healthcare professional
- Since the lesion resembles a melanoma clinically, in majority of cases, a biopsy is performed to exclude a malignant 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 Acral Nevus?
There are frequently no complications that arise from an Acral Nevus.
- Nevertheless, in some individuals, it may give rise to cosmetic concerns
- It may raise a suspicion of a melanoma (a type of skin cancer) in some cases, which may result in undue stress and anxiety
How is Acral Nevus Treated?
The treatment measures for Acral Nevus include:
- The healthcare provider may choose to regularly observe the benign tumor; a “wait and watch” approach may be followed once a diagnosis of Acral Nevus is established. In such cases, no treatment is generally required
- A surgical excision and complete removal of the nevus, to address cosmetic issues or malignancy concerns may be performed
- Follow-up care with regular screening and check-ups are encouraged
It is important to note that a benign Acral Nevus and an early acral lentiginous melanoma may be hard to differentiate using dermoscopy. Hence, any pigmented skin lesion, greater than 0.7 cm (slightly over ¼ inch) should be surgically removed through excision procedure.
How can Acral Nevus be Prevented?
Current medical research has not established a method of preventing the occurrence of Acral Nevus.
What is the Prognosis of Acral Nevus? (Outcomes/Resolutions)
- The prognosis of Acral Nevus is excellent on its complete excision and removal
- Since, these are benign conditions, the prognosis is generally excellent even if only periodic observation is maintained
Additional and Relevant Useful Information for Acral Nevus:
- There is no evidence to prove that the tumor formation is influenced by one’s dietary choices
- 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
- The presence of dirt on the body is not a causative factor for the condition. However, it helps to be clean and hygienic, which may help the condition from getting worse
The following dermoscopic features help in distinguishing an acral melanoma and a benign Acral Nevus.
- Dermoscopic pattern of acral melanoma may be described as having the following features:
- Abrupt edges
- Blue-white veil
- Irregular diffuse pigmentation
- Parallel ridge pattern
- Peripheral irregular dots and globules
- Serrated pattern
- In benign Acral Nevus, the following four dermoscopic patterns can be seen:
- Parallel furrow pattern: Here, the melanocytic pigmentation is visible on the parallel sulci of the skin marking
- Lattice-like pattern: Here, the melanocytic pigmentation follow and crisscross the skin markings
- Fibrillar pattern: Here, the melanocytic pigmentation cross the skin markings diagonally
- Non-typical pattern: Here, the melanocytic pigmentation varies and does not follow typical patterns described
Additionally, in individuals with atypical mole syndrome, three more dermoscopic pigmentation patterns have been described in Acral Nevi, which include:
- Globular pattern: Here, the melanocytic pigmentation is evenly and regularly distributed within the pigmented skin lesion in the form of globules (circular)
- Homogenous pattern: Here, the melanocytic pigmentation is evenly and regularly distributed within the pigmented skin lesion in diffuse light brown or blue color
- Reticular pattern: Here, the melanocytic pigmentation is present as a black/brown mesh-like network