A Spitz naevus (or Spitz's nevus) is an uncommon type of mole (melanocytic naevus). It usually appears on the face or limbs of children and grows rapidly for a few months. After the initial growth period, if untreated, it may remain static for years. Spitz naevi may disappear spontaneously after a period of time.
Spitz naevi are benign (harmless) skin tumours. However, they may resemble malignant melanomas clinically and microscopically.
What do Spitz naevi look like?
Spitz naevi are typically dome-shaped red, reddish-brown (classic Spitz) or darker papules or nodules (pigmented Spitz) and may be up to one or two centimetres in diamater.
How do you get Spitz naevi and who is at risk?
A Spitz naevus is a type of melanocytic naevus, i.e., a mole composed of melanocyes – these are cells that normally produce pigment, melanin, and are responsible for skin colour.
It is not known why Spitz nevi occur. They seen most often in children; 70% of cases diagnosed during the first 20 years of life. They may also arise in adults. They are most frequently found in fair-skinned individuals (skin phototypes 1 and 2).
How are Spitz naevi diagnosed?
Spitz naevi are often suspected clinically by their characteristic dome-shaped appearance and rapid growth over a few weeks to months. Dermatoscopy of a classic Spitz often reveals uniform rounded structures with prominent blood vessels, and in pigmented Spitz may show relatively structureless or globular pigmentation.
An atypical Spitzoid tumour or a Spitzoid tumour of uncertain malignant potential (STUMP) may be difficult to distinguish histologically from Spitzoid melanoma and is best widely excised.
What treatments are available for Spitz naevi?
Because of the difficultly in definitively predicting the outcome of Spitz naevi, it is generally recommended that Spitz naevi are cut out (excised). However, this is not always necessary in children, particularly if the lesions are typical in appearance and remain stable. Some of them eventually disappear by themselves.