A Spitz nevus (also known as an "Epithelioid and spindle-cell nevus," "Benign juvenile melanoma", and "Spitz's juvenile melanoma") is a benign melanocytic nevus, a type of skin lesion, affecting the epidermis and dermis.
Spitz nevus is also known as spindle and epithelioid cell nevus and juvenile melanoma. The latter term is generally no longer used as it is misleading: it is not a melanoma, it is a benign lesion; it can also occur in adults, not only in children.
Spitz nevi are uncommon. Their annual incidence was estimated in a coastal population of sub-tropical Queensland to be 1.4 cases per 100,000 people. For comparison, the annual incidence of melanoma in the same population, which is high by world standards  is 25.4 cases per 100,000 people.
Whilst they are most commonly found on people in their first two decades of life, the age range for people with Spitz nevi is from six months to 71 years, with a mean age of twenty-two years and a median age of nineteen years. 
The cause of Spitz nevi is not yet known. There is an association with sunburn, but causation is not established.  Genetic studies of Spitz nevi have shown that most cells have the normal number of chromosomes, however a minority (25%) of cells have been shown to contain extra copies of parts of some chromosomes, such as the short arm of chromosome 11 (11p). 
of a Spitz nevus showing the characteristic vertically arranged nests of cells ("hanging bananas"). H&E stain
Spitz nevi characteristically have vertically arranged nests of nevus cells that have both a spindled and an epithelioid morphology. Apoptotic cells may be seen at the dermoepidermal junction. The main histologic differential diagnoses are pigmented spindle cell nevus and malignant melanoma.
The lesion is named after Dr.Sophie Spitz, the pathologist who originally described it in 1948.
de:Spitz-N vus pl:Znami Spitz