Spitz Nevus: Symptoms, Types, Causes and Treatment

Spitz nevus is a unique type of skin lesion that can create both medical curiosity and clinical concern. Often appearing in children and adolescents, these growths are benign, but they can closely mimic melanoma, a dangerous form of skin cancer. This resemblance makes understanding, diagnosing, and managing Spitz nevi especially challenging for patients and clinicians alike. In this article, we provide a comprehensive look at the symptoms, types, causes, and treatment options for Spitz nevus, synthesizing the latest evidence to help you better understand this intriguing skin condition.

Symptoms of Spitz Nevus

Spitz nevi often present themselves in distinctive ways, but the variability in appearance can make them difficult to identify without clinical expertise. Recognizing the typical symptoms is crucial for early detection and appropriate management, especially given their similarity to melanoma.

Appearance	Age Group	Location	Source(s)
Dome-shaped, papular, or nodular lesion; may be pigmented or nonpigmented	Most common in children and adolescents; rare in adults	Lower extremities most common, then trunk, head/neck more common in children	3, 4, 7
Color varies from pink/red (classical) to brown/black (pigmented variant)	First decade of life (children), but can occur at any age	Pigmented types more frequent on lower extremities; nonpigmented on head/neck	2, 3, 7
Size usually <1 cm; may rarely be larger	Female predominance in adults	Lesions may be solitary or, rarely, multiple (agminated)	3, 7, 5
May show rapid initial growth, then stabilize	—	—	3, 12

Table 1: Key Symptoms

Clinical Appearance

Spitz nevi most often appear as small, dome-shaped, or raised papules and nodules on the skin. They can be either pigmented (brown to black) or nonpigmented (pink to red), with the pigmented form being more prevalent than previously thought 2, 3. The classical Spitz nevus is pink or red, but dermoscopy reveals that pigmented variants are actually more common.

• Size: Typically less than 1 cm in diameter, although larger lesions have been documented, particularly in genetic variants (agminated Spitz nevi) 5.
• Surface: The surface is usually smooth, and the lesion can be symmetrical, although not always.

Age and Demographics

Spitz nevi predominantly affect children and adolescents. Most cases are diagnosed in the first decade of life, with a slight female predominance, especially among adults 3, 7.

• Children: Over half of all Spitz nevi are diagnosed in children younger than 10 years old.
• Adults: Far less common, but when they do occur, they are more frequent in women 7.

Location on the Body

The most frequent site for Spitz nevi is the lower extremities, followed by the trunk. The head and neck region is a common location in children, especially for nonpigmented forms 3, 7.

Growth Pattern

A Spitz nevus may grow rapidly over a period of weeks or months before reaching a plateau and remaining stable. This growth spurt can sometimes cause alarm but is typical for this lesion type 3, 12.

Other Symptoms

Spitz nevi are usually asymptomatic, meaning they do not cause pain or discomfort. They are most often discovered incidentally or because of concern about a changing skin lesion.

Types of Spitz Nevus

Spitz nevi are not all alike; they vary in appearance, cell type, and even underlying genetic features. Understanding the different types assists both diagnosis and management.

Type	Cell Predominance	Frequency / Age Group	Source(s)
Junctional	Epidermal	More common in children	4, 5
Compound	Epidermal/Dermal (mixed)	Most frequent overall; younger patients	1, 4, 7
Dermal	Dermal	More common in adults; older patients	4, 7
Pigmented	Both cell types	Majority of cases (over 70%)	2, 3
Nonpigmented	Both cell types	Less common; usually head/neck	2, 3
Agminated	Various	Multiple lesions clustered; rare	5, 9
Atypical/Spitz Tumor	Atypical features	Intermediate between Spitz nevus and melanoma	2, 7

Table 2: Spitz Nevus Types

By Histological Architecture

• Junctional Spitz Nevus: Melanocytes are present at the junction of the epidermis and dermis. More frequently seen in children 4.
• Compound Spitz Nevus: Involves both the epidermis and the dermis; this is the most common subtype 1, 4, 7.
• Dermal Spitz Nevus: Melanocytes are located only in the dermis. More typical in adults and older lesions 4, 7.

By Cellular Characteristics

• Epithelioid Cell Type: Cells are large, round, and have abundant cytoplasm.
• Spindle Cell Type: Cells are elongated and resemble spindles.
• Mixed: Many Spitz nevi contain both cell types, which is a hallmark of this lesion 7.

Pigmented vs. Nonpigmented

• Pigmented Spitz Nevus: More common than previously thought, often found on the lower extremities, and composed of spindle or mixed cells 2, 3.
• Nonpigmented (Classical) Spitz Nevus: Pink or red, more frequent on the head or neck, especially in children 2, 3.

Special Variants

• Agminated Spitz Nevus: Multiple Spitz nevi occurring in a cluster or within a larger pigmented patch, such as a nevus spilus. These may show unique genetic features 5, 9.
• Atypical Spitz Tumor: Lesions that have features intermediate between a benign Spitz nevus and spitzoid melanoma. They may require more aggressive management due to their uncertain behavior 2, 7.

Causes of Spitz Nevus

Understanding why Spitz nevi develop involves looking at both genetic and environmental factors. Although most cases arise without a clear trigger, recent research has shed light on underlying molecular mechanisms.

Factor	Description	Evidence	Source(s)
HRAS mutations	Activating mutations, especially in some subtypes	Molecular studies	6, 9
Chromosome 11p gains	Leads to increased HRAS copy number	FISH/genetic studies	6
Gene rearrangements	Involving TRPM1, PUM1, LCK in rare cases	Case reports	9
Mosaicism	Genetic changes affecting clusters of cells	Observational	5, 9
Unknown/idiopathic	Most cases have no identifiable cause	Clinical observation	7, 14

Table 3: Causes and Genetic Factors

Genetic Factors

HRAS Mutations and Chromosome 11p Gains

• A significant subset of Spitz nevi show increased copies of chromosome 11p, which contains the HRAS gene. These copy number gains, and activating mutations in HRAS, are linked to particular histologic features: larger size, intradermal location, and desmoplasia 6.
• HRAS activation in the absence of additional mutations appears to drive benign growth and may explain why these nevi do not progress to melanoma 6.

Gene Rearrangements

• Rarely, unique gene fusions involving TRPM1, PUM1, and LCK have been described in agminated Spitz nevi, expanding the genetic spectrum associated with these lesions 9.

Mosaicism

• Some agminated (clustered) Spitz nevi arise within a background of nevus spilus—a larger pigmented patch. Genetic mosaicism, where only a subset of skin cells have specific mutations, is likely involved in these cases 5, 9.

Environmental and Unknown Factors

• No consistent environmental cause (such as sun exposure or trauma) has been identified.
• Most Spitz nevi arise spontaneously, especially in children 7, 14.

Treatment of Spitz Nevus

Treatment of Spitz nevi is one of the most debated topics in dermatology due to the difficulty in distinguishing them from melanoma. Management strategies depend on the patient's age, the lesion's characteristics, and the level of clinical suspicion.

Approach	Indication	Comments / Consensus	Source(s)
Surgical excision	Lesions suspicious for melanoma or atypical; adults	Most recommended; narrow margins (1-2 mm)	2, 10, 11
Biopsy (total)	Diagnosis confirmation	Preferred over partial in children	10, 12
Clinical follow-up	Typical, stable lesions in children	Conservative approach gaining favor	12, 13, 14
Re-excision	Incompletely excised or atypical lesions	Narrow margins; more aggressive if atypical	10, 11
Dermatoscopy	Evaluation tool	Helps identify typical patterns	12, 13

Table 4: Treatment and Management Strategies

Surgical Excision

• When is excision recommended?
  • Most dermatologists recommend complete surgical removal when a Spitz nevus is clinically or histologically suspicious for melanoma, is atypical, is found in an adult, or is incompletely excised 2, 10, 11.
  • Excision margins are typically narrow (1-2 mm), especially in children. Wider margins may be used at the discretion of the clinician 10, 11.

Biopsy

• Total vs. Partial Biopsy
  • Total excisional biopsy is preferred, especially in children, because partial biopsy may miss features necessary for accurate diagnosis 10, 12.
  • Partial biopsies are generally avoided due to the risk of sampling error.

Clinical Follow-Up

• Conservative Management in Children

  • For typical, stable, and nonpigmented Spitz nevi in children, nearly half of pediatric dermatologists opt for clinical observation rather than immediate surgery 12, 13.
  • Dermatoscopic monitoring can help track changes over time and avoid unnecessary excision.

• When is follow-up appropriate?

  • Small, stable lesions in children without alarming features.
  • Lesions with a characteristic starburst pattern on dermoscopy 12, 13.

Re-Excision

• If a Spitz nevus is incompletely removed, especially if it shows atypical features, re-excision with a narrow margin is often recommended 10, 11.

Dermatoscopy

• Used by the majority of pediatric dermatologists as a non-invasive tool to help differentiate Spitz nevi from melanoma and guide management 12, 13.

Special Considerations

• Atypical Spitz Tumors: Lesions with features between Spitz nevus and melanoma often require more aggressive management due to uncertainty about their behavior 2, 11.
• No Standardized Guidelines: There is no universally accepted guideline for management. Physicians often tailor their approach based on patient age, lesion features, and institutional protocols 14.

Conclusion

Spitz nevus is a fascinating and often perplexing skin lesion that can pose diagnostic and management challenges. Understanding its symptoms, subtypes, causes, and treatment options is essential for both clinicians and patients.

Summary of Key Points:

• Symptoms: Usually presents as a dome-shaped, pigmented or nonpigmented papule or nodule in children and adolescents, most commonly on the lower extremities 3, 7.
• Types: Includes junctional, compound, and dermal variants; pigmented and nonpigmented forms; and rare types like agminated and atypical Spitz nevi 1, 2, 4, 5.
• Causes: Mainly linked to genetic mutations (especially HRAS), chromosomal gains, and, rarely, gene rearrangements; most cases are idiopathic 6, 9.
• Treatment: Ranges from surgical excision (especially in adults and atypical cases) to conservative follow-up for typical lesions in children; no universal consensus exists 10, 12, 14.

By staying informed and working closely with dermatology professionals, patients and families can navigate the complexities of Spitz nevus and ensure the best possible outcomes.