A Spitz nevus is a non-cancerous skin growth often mistaken for melanoma, a serious form of skin cancer. This benign lesion commonly appears as a mole-like growth. Its resemblance to melanoma makes it a diagnostic challenge. Understanding its characteristics is important for distinguishing it from more concerning skin conditions.
Understanding Spitz Nevus
A Spitz nevus is a type of benign melanocytic nevus, a mole composed of melanocytes, the skin’s pigment-producing cells. Historically, they were called “benign juvenile melanoma” due to their microscopic resemblance to melanoma. However, this term is misleading because Spitz nevi are not cancerous and do not behave like melanoma.
The term “juvenile melanoma” is no longer used, as these lesions are neither true melanoma nor exclusively found in children. While they can occur at any age, Spitz nevi are more common in children and young adults, with many diagnoses in individuals under 20. The exact cause is unknown, though some cases show genetic differences from melanoma.
How Spitz Nevus Appears
A Spitz nevus typically appears as a dome-shaped, raised growth. Its color varies widely, from pink, red, or reddish-brown to tan or black. These lesions are usually small, often a few millimeters to one or two centimeters in diameter. The surface is generally smooth but can sometimes have a warty texture.
Spitz nevi often appear suddenly and can grow rapidly for a few months, usually reaching full size within six months. After this initial growth, the lesion typically stabilizes and may remain unchanged for years. While usually solitary, multiple lesions can occasionally erupt. Common locations include the face, limbs, and trunk.
Differentiating Spitz Nevus from Melanoma
Distinguishing a Spitz nevus from melanoma is a significant challenge, even for experienced dermatologists, due to their overlapping features. Both lesions can appear similar, leading to diagnostic uncertainty. Therefore, professional medical evaluation is essential for accurate diagnosis.
Unlike melanoma, which often displays asymmetry, irregular borders, varied colors, and a diameter larger than 6mm, a classic Spitz nevus tends to be symmetrical and uniformly colored. While a Spitz nevus can grow rapidly, its growth usually stabilizes after a few months, whereas melanoma often continues to evolve. Features like bleeding or itching can occur in both, making visual differentiation difficult.
Dermatologists often use dermoscopy, a non-invasive imaging technique, to examine the lesion more closely. This tool can reveal characteristic patterns within the Spitz nevus, such as uniform rounded structures or a “starburst pattern,” aiding in diagnosis. However, a definitive diagnosis frequently requires surgical removal of the lesion for microscopic examination.
Diagnosis and Treatment Approaches
The diagnostic process for a suspected Spitz nevus typically begins with a clinical examination by a dermatologist. Dermoscopy is often used to magnify the lesion and observe its internal structures and pigment patterns. While these initial steps provide strong indications, they are often not sufficient for a definitive diagnosis due to the resemblance to melanoma.
A definitive diagnosis usually requires an excisional biopsy, surgically removing the entire lesion. The tissue is then sent to a dermatopathologist, a specialist who examines it under a microscope to differentiate between a benign Spitz nevus and melanoma. This microscopic analysis is important for ruling out cancer.
If definitively diagnosed as a benign Spitz nevus, observation may be sufficient, especially in children, as some can spontaneously disappear. However, surgical excision might still be recommended for diagnostic uncertainty, atypical features, or cosmetic reasons, particularly in older children and adults. Regular follow-ups with a dermatologist are advised to monitor any changes.