Speckled Lentiginous Nevus - Symptoms, Diagnosis, and Treatment

Introduction

Speckled lentiginous nevus (SLN) are macular or papular melanocytic lesions (noncancerous skin patch) consisting of several dark brown or black macules (café au lait). It is also commonly known as “nevus spilus.” Due to the loss of phenotypic expression (genetic growth and development), speckled lentiginous nevus (SLN) represents a mosaic phenotype (type of genetic trait). They have a male-to-female ratio of 4:3 and are present at birth, though they can also emerge during the first years of life.

What Is Speckled Lentiginous Nevus (SLN)?

Speckled lentiginous nevus (SLN) is also associated with the following:

1. Segmental Neurofibromatosis Type 7 - It is a rare neurofibroma.

2. Phacomatosis Pigmentovascularis - It is characterized by the presence of pigmentary and vascular birthmarks.

3. Phacomatosis Pigmentokeratotica - It is a type of pigmented noncancerous skin patch.

Researchers have recently identified speckled lentiginous nevus (SLN) as a neurocutaneous phenotype associated with ipsilateral neurological dysfunction (one-sided abnormality in brain function), such as:

1. Hyperhidrosis (excessive sweating).

2. Muscle weakness.

3. Dysesthesia (abnormal sensation).

4. Nerve palsies with nerve thinning.

5. Atrophy of the spinal muscles with fasciculations (twitching of the muscles).

What Is the Prevalence of Speckled Lentiginous Nevi (SLN)?

• The prevalence of speckled lentiginous nevi is comparable to that of congenital melanocytic nevi, ranging from 0.2 to 2.3 % depending on age.

• The researchers have studied the prevalence in Asian and white European children, which is the same in both ethnic groups.

• There is no discrimination based on race or sexual orientation.

• The researchers have also reported low prevalence rates of up to 0.2 % in newborns.

• Around 80 % of speckled lentiginous nevi appear at birth or early childhood.

• They can begin as light-colored café au lait macules at birth and progress to hyperpigmentation and darkly pigmented macules and papules over months, years, or even decades.

What Are the Types of Speckled Lentiginous Nevus (SLN)?

Speckled lentiginous nevus (SLN) is classified into two types:

1. Macular Speckled Lentiginous Nevus (SLN)- It is commonly associated with phacomatosis spilorosea (phacomatosis pigmentovascularis type 3), a variety of pigmented noncancerous skin patches.

2. Papular Speckled Lentiginous Nevus (SLN)- This type of nevus is commonly found in phacomatosis pigmentokeratotica(pigmented noncancerous skin patch).

What Are the Features of Speckled Lentiginous Nevi (SLN)?

• Speckled lentiginous nevi can occasionally affect a large portion of the body.

• The overall shape can be blocklike or parallel, and the distribution patterns are frequently described as zosteriform (rash).

• Furthermore, the parallel lesions may follow the Blaschko lines, a pattern linked to embryonic development.

• A divided form of speckled lentiginous nevus also involves both the upper and lower eyelids.

• This features the most likely timing of nevus formation during embryogenesis, which occurs after the eyelid fuse in the eighth to the ninth week of pregnancy but before the eyelid reopens in the sixth month.

• The spots of a speckled lentiginous nevus typically have a diameter of 1 to 3 mm, though occasionally, they can be more extensive.

• The clinical appearances and histologic features of speckles can vary greatly.

• Notably, a speckled lentiginous nevus may develop various types of spots at different points in its lifespan.

• For example, a child described having multiple Spitz nevi within his speckled lentiginous nevus at three. Still, when examined at thirteen, he had multiple blue and compound nevi within the lesion.

• Some studies have linked the progression of the nevi to factors such as sun exposure and pregnancy.

What Are the Histologic Findings in Speckled Lentiginous Nevi (SLN)?

1. In the hyperpigmented macule, there is increased pigmentation in the basal layer of the epidermis.

2. Small nests of increased melanocytes are occasionally observed and are referred to as nevus incipient.

3. Biopsy samples from the speckled areas reveal a variety of findings, including:

• Junctional lentiginous nevi (located in the outer and the inner layers of skin).

• Compound and intradermal nevi (mixed type of nevi).

• Compound or intradermal nevi with congenital features (found in the inner surface of the skin).

4. Sometimes there are collections of dermal melanophages (large bright, plump cells) without an inflammatory infiltrate.

What Is the Patient Management for Speckled Lentiginous Nevi (SLN)?

The most appropriate treatment is a baseline lesion assessment, followed by close clinical monitoring annually or more frequently if the lesion changes.

• Baseline photography may help with accurate monitoring.

• It is critical to educate the family and patient about the signs of melanoma, how to monitor the lesion at home, and the ABCDEs:

A- Asymmetry.

B- Border.

C- Color.

D- Diameter.

E- Elevation.

• It should be stated that the risk of progression to melanoma is shallow, but there is a risk, and ongoing monitoring is required.

• Suppose a melanoma is found in an NS lesion. In that case, the standard treatment is the excision of the entire pigmented patch followed by punch excision of the remaining speckled areas of the lesion.

What Is the Treatment for Speckled Lentiginous Nevi (SLN)?

Surgery-

For some patients, surgical removal is a viable treatment option. Since speckled lentiginous nevus is a defect in the melanoblasts localized to an area of skin, the entire area of hyperpigmentation must be excised to prevent a recurrence. However, scarring can be severe.

Laser Therapy-

Q-switched ruby or Q-switched neodymium-doped yttrium aluminum garnet (Nd: YAG) lasers have been used to treat hyperpigmented and speckled lentiginous nevi speckles. However, cosmetically, the results have not been promising and the laser’s use to treat speckled lentiginous nevi is still debatable.

What Is the Justification for Treating Speckled Lentiginous Nevi (SLN)?

Speckled lentiginous nevi (SLN) is a benign lesion that does not need to be treated. However, some patients may be concerned about the cosmetic appearance if the lesion is on the face. In some circumstances, a wide excision may be done, but a large scar’s visual must be considered. Laser ablation is not recommended because it may make it more challenging to monitor and assess the lesion for change. If risk factors for melanoma (malignancy) are present, such as the lesion being more significant than 4 cm in size, it should be closely monitored by the patient and a dermatologist. If the lesion progresses to melanoma, appropriate management is required.

Conclusion

For early detection of atypical features within a speckled lentiginous nevus, it is recommended to visit a dermatologist regularly and get a careful examination with the use of photography. In addition, consult a dermatologist if there is any doubt about the diagnosis or treatment of melanocytic neoplasms in general or speckled lentiginous nevus in particular.